SPANISH
The presentation by Leica of the new Apo-Summicron-M 50 mm f/2 ASPH lens during an event held in Berlin on May 10, 2012, was an outstanding surprise bringing about high levels of expectation, since until that moment it was thought that the Summilux-M 50 mm f/2 ASPH designed by Peter Karbe, introduced in 2004 and till recently with difference the best 50 mm lens in the world (followed from a short distance by the Nikkor-S 50 mm f/1.4 for the Nikon S3 Milennium launched in 2000), was practically impossible to beat in optical and mechanical quality by any 50 mm of any luminosity, while the Summicron-M 50 mm f/2 without aspheric elements or floating elements, featuring a Double Gauss formula and taken to the last boundaries of the scientifically feasible by Walter Mandler in 1979, was likewise very difficult to improve with a f/2 design, and was along with the Carl Zeiss C 50 mm f/2 ZM the best 50 mm lens available in that luminosity.
But the MTF curves of the new Apo-Summilux-M 50 mm f/2 ASPH prove that this new image quality world benchmark in 50 mm standard focal length for full frame 24 x 36 mm (which reaches on this format an image quality comparable to Large Format 4 x 5" -10 x 12 cm- cameras with the Leica M9 and M9-P and of 5 x 7 " -13 x 18 cm- Large Format cameras with the Leica Monochrom) beats the four 50 mm lenses which were the flagships until very recently (Summicron-M 50 mm f/2 versions 4 and 5, Carl Zeiss Planar 50 mm f/2 ZM, and above all the Nikkor-S 50 mm f/1.4 for Nikon S3 Millennium 2000 and the Summilux-M 50 mm f/1.4 ASPH - both of them being the two best 50 mm lenses ever made till the appearance of the Apo-Summicron-M 50 mm f/2 ASPH-), roundly beating them, specially on borders and corners, where as we´ll see, the new Apo-Summicron-M 50 mm f/2 ASPH reaches stratospheric and unprecedented levels of excellence, with a luminic evenness and an optical performance in both resolving power and contrast on the whole image surface that is going to undoubtedly mark
a before and after in the History of Photography, opening a new stage within the digital era, in which the sheer uncompromising optical quality will be even more decisive than in the analogue stage, not only to get maximum possible image quality, but also to have RAW (DNG) archives without any correction through software, enabling to work in postproduction with much higher speed and manoeuver margin without image degradation than with the lenses featuring a strong correction through firmware (which are on the other hand much cheaper to design and make, delivering optical and mechanical qualitative levels that are very far from the ones rendered by the Leica M Digital 24 x 36 mm aspherical lenses).
Besides, if you work with superb lenses, little correction labour will remain to be done, with the added benefit that the professional photographer or advanced connoisseur will be able to use those highly luminous objectives for many decades, without depending on aberrations correcting firmwares built into lenses or cameras or softwares for ´development´ of RAW archives or the typical different image qualities delivered by the firmware corrected lenses, which often yield different results according to the brand of the camera they are connected to, in spite of featuring the same size of sensor inside.
Needless to say that the highly luminous Leica M lenses for full frame 24 x 36 mm format - in the same way as the lenses for excellent full frame 35 mm reflex cameras like the Nikon D800, Nikon D4, Nikon D3, Canon EOS 5D (it will be interesting to see the results obtained with the just announced Sony Alfa 99, whose features are very promising) and others) provide among many other advantages to be able to easily take pictures with selective focus at the widest diaphragms, so they can highlight the photographed persons or subjects with respect to the background, a context in which the cameras lacking a rangefinder and featuring small format sensors under the APS-C size, have a lot of difficulties, because the depth of field they get at identical f stops is much bigger.
It must also be underlined the highly significant fact that the Apo-Summicron-M 50 mm f/2 ASPH, created to match the state-of-the-art sensor of the Leica M Monochrom, achieves something that was deemed in the frontier of the impossible: to improve the extraordinary contrast boasted by both Mandler´s Summicron-M 50 mm f/2 Versions 4 and 5 and Peter Karbe´s Summilux-M 50 mm f/1.4 ASPH, which were until now with difference the unchallenged benchmarks in this scope.
Therefore, the Apo-Summicron-M 50 mm f/2 ASPH is beyond doubt the most perfect 50 mm lens ever made in the world, praiseworthily synthesizing Leica´s traditional strenuous effort to offer with its lenses the same excellent image quality taking pictures at every diaphragm between full stop and around f/8, in such a way that on stopping down you will only win depth of field, something only attainable by the cream of lenses following the parameters of the axiom: You pay for the performance, often being limited by diffraction from f/5.6.
On the other hand, the times in which the design of lenses were essentially made with the old method, through manual calculi, in the purest style of Max Berek or Ludwig Bertele are far behind, and nowadays, Leica, fully aware about the significance of Computer Science in the creation of lenses (in 1952 Leica was the world pioneer in the use of computers for the design of photographic objectives, with the giant 2 ton and 40 Hz giant computer Z5 in Wetzlar - the first one existing in Canada was an IBM 604 two years later-, replaced in 1958 by a new Elliot 402F English computer, optimized for the tracing and recording of light rays, which was installed in the factory of Leitz Midland, Ontario, Canada - shortly after, another identical one was installed in Wetzlar- saving a lot of hours of work in different sides, among them the manual tracing of the light rays during the design), is also in this sphere, such as we´ll see later, at the cutting edge of the world photographic industry,
currently using the best computers and software programs in existence intended for such purpose.
But that is not enough to reach the level of quality achieved by Leica, so such superb ultramodern computers and lens design software programs of its own optimized for lens design ( which are the present technological state-of-the-art in such matter) are complemented by the huge expertise and knowledge of its optical and mechanical engineers, who know which are the questions to be asked to the computers in order to get the maximum optical and mechanical quality in the smallest size and weight of lens feasible (so attaining a very efficient combination of very big 24 x 36 mm sensor and very small Leica M Lenses coupled to also very little Leica M Digital full frame cameras, featuring exceedingly reduced dimensions and weight, and including a masterpiece rangefinder, all of which is a key distinctive distinctive factor, because everybody is able to reduce the size of the lenses reducing the size of the sensors, and besides, the smaller sizes of sensor make much easier and much cheaper to design and manufacture lenses giving less divergent rays on the image borders and corners) and have enough know-how to get the most (other way, it would be impossible) of the very updated computers currently used by Leica, optimized for the design and manufacture of highly luminous aspherical lenses, and which interact with design softwares made by themselves and the personal touches provided by the optical and mechanical designers and engineers, who go far beyond the automatic optimization of optical improvement, which is not enough by itself to achieve the second to none image quality and the very small size and weight for its format of Leica M Lenses, because on starting any way or path of computerized design with such extraordinary optical and mechanical quality levels and so large maximum diaphragms apertures, both the size and the weight soar a great deal.
Therefore, the impressive image quality attained by the very small and light Leica M Lenses (world benchmark in optical and mechanical quality in the 35 mm format domain) stems in a nutshell from the combination of an exceptional optical prowess with exceedingly advanced technologies of manufacturing of lenses, which are the outcome of highly complex optical calculi and very deep mathematical and physics knowledge, along with a great mastery of the nanometric scale, an environment in which the Leica laser interferometers make up the cornerstone to carry out the measurements of the quoted so small scale when tackling the making of the optical elements, in such a way that usually, the measuring instruments are even more accurate than the manufacturing machines.
Besides, the curvature of Leica M aspherical lenses (not hybrid, moulded or plastic, but made with the best optical glasses available, either optical glass blanks pressed up to a diameter of around 20 mm through a state-of-the art technology or aspherical elements featuring larger diameters and grinded and polished with CNC machines) has to be created with utmost precision, which entails a huge complexity, increasing even more during the ultrasonic cleaning of the already polished aspherical elements and the highly sophisticated subsequent stage of computerized multicoating.
If we add to it that Leica has implemented since 2008 a quantum leap in optical development regarding new available technologies related to the treatment of the aspherical elements, new methods of assembly, revolutionary centering techniques, etc, we can understand how in a period of only seven years, Leica has been able to turn into a very important firm of the digital photographic industry at international level, consolidating even more its position as world reference of optical and mechanical quality of lenses, something of which the Apo-Summicron-M 50 mm f/2 ASPH is a clear example, opening an even more promising future for Leica, whose Leica M Digital System is at present hugely consolidated.
with the mirrorless cameras featuring a rangefinder Leica M9, M9-P and Monochrom, in synergy with the best full frame 35 mm existing lenses, when only three years have elapsed since the mythical German photographic firm managed to attain the technological feat of manufacturing a full frame rangefinder camera boasting a 24 x 36 mm sensor after some years of arduous work.
Though MTF curves are not the last word regarding the image quality achieved by a lens (there are other essential factors like the evaluation by professional photographers, the mechanical construction, the quality level of the digital sensor, the quality and speed of the DSP, the acutance, the great honesty and huge self-exactness applied by Leica.
when making the contrast and resolution tests, subsequently publishing the MTF graphs of its aspheric lenses (with continuous sagital and tangential lines for nothing less than three different diaphragms - usually the two ones being most luminous and a third one which is often f/5.6 -, along with four different measurements: contrast lines for 5lp/mm and 10 lp/mm and resolution lines for 20 lp/mm and 40 lp/mm as to the sharpness obtained with the most hidden structures and details of the photographed subjects), result in a very high reliability.
This way, unlike other MTF curves of different brands often only showing values for maximum aperture and f/8 with the reference of merely two pairs of sagital continuous and discontinuous lines barely giving information on the homogeneity or not of optical quality on different areas of the image surface at various f stops (above all in the two being most luminous), in Leica MTF you can check the exceedingly important factor of amazing uniformity in superb optical performance from the widest aperture until around f/8, which is one of the cornerstones of the German firm in the design of their lenses.
All lenses deliver a good image quality at f/8, so when sometimes some people speak about excellent image quality of a prime or a zoom lens of various brands at such an aperture of diaphragm, suggesting that the lens features a high quality level, vast majority of times it is simply not true, because in addition to resolving power and contrast, the level of mechanic building and other sides, the image quality delivered by a lens at full aperture is the most differentiating and significant factor to grasp its real capabilities, above all if it belongs to the selected goup of the very few truly able to achieve practically identical superb level of image quality both at maximum aperture and stopping down, on the whole image surface, from center to borders and corners, so Leica MTF curves, highly scientifical and serious, provide very valuable and reliable information on resolving power, sharpness, contrast, kind of bokeh, correction of optical aberrations, etc.
Let´s see then in-depth the most significant traits of the Apo-Summicron-M 50 mm f/2 ASPH, which do speak for themselves to a great extent.
APO-SUMMICRON-M 50 MM F/2 ASPH AT MAXIMUM APERTURE F/2
In both lines of contrast for 5 lp/mm, the Apo-Summicron-M 50 mm f/2 ASPH
flatly beats Mandler´s Summicron-M 50 mm f/2 Versions 4 and 5,
On its turn, the continuous sagittal red line of contrast for 10 lp/mm (the second one beginning from top of the graph) also indicating the contrast ratio for structures of large objects, reaches a value of 97 % in the center of the image, which keeps on and superposes with the discontinuous tangential red line for 10 lp/mm up to 6 mm from the image center, both of them going on superposed up to 7.5 mm from the image center (value of 96.5 %), and start their separation at 9 mm from the image center (with a value of 95 %), and from this point onwards, in the same way as happened with the discontinuous tangential red line of 5 lp/mm, the discontinuous tangential red line of 10 lp/mm shows an amazing uniformity of optical performance between the image center (value of 97 %) and the corner (value of 96%), with a maximum quality level of 96.5 % at 12 mm and 15 mm from the center and 96.2 % in the border (at 18 mm from the image center), going on practically parallel from the center up to the corner in regard to the dicontinuous tangential red line of contrast for 5 lp/mm, while the continuous sagittal red line of contrast for 10 lp/mm begins its progressive descent at 9 mm from the center (value of 95 %), which drops to 90% at 12 mm from the center, 85 % at 15 mm from the center, 80 % at 17 mm from the center, 78 % at 18 mm (id est, in the border of the image) from the center and 73 % on the corner.
Likewise, in both red lines of contrast for 10 lp/mm, the Apo-Summicron-M 50 mm f/2 ASPH
whose continuous sagittal red line of contrast for 10 lp/mm gets a value of 92 % in the center (97 % the Apo-Summicron 50 ASPH), 72 % in the border (96. 2 % the Apo-Summicron 50 ASPH) and 54% in the corner (73 % the Apo-Summicron M 50 mm f/2 ASPH); while the tangential discontinuous red line of the Summicron-M 50 mm f/2 obtains a value of 92% in the center (97 % the Apo-Summicron 50 ASPH), 86 % in the border (96.2 % the Apo-Summicron 50 ASPH) and 80% in the corner (96% the Apo-Summicron 50 ASPH).
The values displayed by these two MTF graphs for 5 lp/mm and 10 lp/mm at f/2, prove that the Apo-Summicron-m 50 mm f/2 ASPH is clearly better in contrast - above all in borders and corners - than the Summicron-M 50 mm f/2 Versions 4 and 5 (something really astonishing, since the contrast of both Summicron-M 50 mm f/2 featuring identical optical formula is superb and much more than enough for vast majority of photographic assignments).
Furthermore, though with a not so big difference, the Apo-Summicron-M 50 mm f/2 ASPH also beats clearly in contrast at f/2 the Summilux-M 50 mm f/1.4 ASPH, above all in borders and corners, something which was deemed impossible until very recently, because the Summilux-M 50 mm f/1.4 ASPH, likewise designed by Peter Karbe, was till now the best 50 mm lens ever, delivering an extraordinary optical performance at f/2 (bettering the Summicron-M 50 mm f/2 at f/2, f/2.8, f/4 and f/5.6), and with a praiseworthy evenness of resolving power and contrast between center, borders and corners of the image which has been beaten by the Apo-Summicron-M 50 mm f/2 ASPH, taking it to the extreme corners of image surface, however incredible it may seem.
This way, it´s apparent that the Apo-Summicron-M 50 mm f/2 ASPH renders a contrast that can be unreservedly defined as stratospheric at f/2 in center and borders of the image and outstanding on the corners, such as is clearly proved by the continuous sagittal red lines and discontinuous tangential red lines of contrast for 5 lp/mm and 10 lp/mm of the MTF graph at widest f/2 aperture.
On its turn, the continuous sagittal red line for resolution of the finest structures for 20 lp/mm (the third one from top of the graph) gets a value of 91 % in the image center, superposing with the discontinuous tangential red line of resolution of fine details for 20 lp/mm up to a distance of 3.4 mm from the center of the image, a point in which the continuous and discontinuous lines begin to separate very slightly, until arriving at 5 mm from the center of the image (value of 90.8 % for the continuous line and 90.4 % for the discontinuous one) and at 6 mm from the center (value of 90.5 % for the continuous line and 90 % for the discontinuous one).
From this spot onwards, we can see an impressive optical feat, because in order to compensate the fact that from 8.5 mm with respect to the center of the image there´s an inevitable descent of the continuous sagittal red line for 20 lp/mm (86% at 9 mm from the center, 78% at 12 mm from the center, 72% at 15 mm from the center, 68% at 18 mm from the center - already in the border of the image - and a 62% on the corner of the image), the designer manages to achieve that the discontinuous tangential red line for resolution of the finest structures at 20 lp/mm (which falls slightly between 3 mm - value of 81 % -, 6 mm - value of 89% - and 9 mm - value of 87% -), rises again until reaching a value of 87.5 % at 12 mm from the center and 88% at 13.5 mm from the center, spot in which it starts an admirable and exceedingly difficult to attain ascent until arriving at 15 mm from the center, with a resolution value of 88.6 %, which incredibly keeps on practically unaltered even at 18 mm from the center (border of the image), and only falls again, in a very slight way, up to a value of 87 % at 21 mm (id est, in the very corner of the image) from the center.
Regarding the continuous and discontinuous red lines of resolution for 20 lp/mm at f/2, the Apo-Summicron-M 50 mm f/2 ASPH
And finally, the continuous sagittal red line of resolution for 40 lp (the fourth one beginning from top of the graph) also corresponding to resolution of details of fine structures, starts with an extraordinary value in the center for f/2 aperture of 73%, superposing with the discontinuous tangential line of resolution for 40 lp/mm up to 1.5 mm from the image center, point from which the continuous sagittal red line increases its quality even more until reaching a resolution value of 73.5 %, maintaining it up to 5 mm from image center, where it begins a slight descent until arriving at 6 mm from image center, a spot in which it still keeps a value of 73.2 %, very slightly superior to the center of the image (0 of the horizontal axis), and from here onwards, there´s a progressive drop (60% at 10.8 mm from the center, 57% at 12mm from the center and 53% at 15 mm from the center), point from which the optical designer has made a titanic effort of balance searching for maximum feasible optical performance in resolving power, increasing the value until attaining a 55% at 20 mm from the center of the image, falling very mildly up to a value of 54% (identical one to the border) on the corners.
On its turn, the discontinuous tangential red line of resolution for 40 lp/mm also corresponding to resolution of fine structures and details, shows an astounding behaviour, not only in terms of sharpness but also in optical performance uniformity: it begins with a value of 73.5 % in the image center, superposing with the continuous sagittal red line for 40 lp/mm up to 1.5 mm from the image center, point from which both of them start separating, and descends very slightly until getting a value of 72.5 % at 3 mm from the center, keeping on its slight dropping trajectory until arriving at 6 mm from the center, where it reaches a value of 68%, and goes on up to 8 mm from the image center, where it achieves a value of 67 %.
From here on, there´s a titanic effort by the lens designer in order to preserve the huge resolving power both in the center and in borders and corners, because from a distance of 9 mm to the center of the image takes place a visible increase of quality until arriving at 12 mm from center (with a value of 67.5%). And from this spot onwards, a new quality rise - even of a higher level- develops, resulting in attaining a value of 69.5 % at 14 mm from the image center, 70 % at 15 mm from the center and 71.5 % at 16.5 mm from the center, that´s to say, a value very near the 73.5% of the image center but now on an area close to the border!, arriving at 18 mm from the center (already in the border of the image) with a value of 71.2 %, a point from which it begins a very slight descent, getting a value of 70.5 % at 20 mm from the image center (already almost on the corner) and 69.5% at 21 mm from the center (already on the very corner).
And equally for these two lines for 40 lp/mm at f/2, the Apo-Summicron-M 50 mm f/2 ASPH
On the other hand, the aforementioned great height for different values of the MTF graph at f/2 of this unmatched Apo-Summicron-M 50 mm f/2 ASPH lens, along with the amazing proximity of the continuous and discontinuous lines (with the huge constructive difficulty it requires for such a small size, weight and diameter of objective) that even superpose utterly up to 7.5 mm from the image center (continuous and discontinuous lines of contrast for 5 lp/mm) and 8 mm from the image center (continuous and discontinuous lines of contrast for 10 lp/mm), together with the great level of quality and remarkable optical performance homogeneity of the continuous and discontinuous resolution lines for 20 lp/mm and 40 lp/mm, unmistakably reveal that the Apo-Summicron-M 50 mm f/2 ASPH features an extraordinary contrast at its widest aperture, along with a staggering resolution, bearing in mind such maximum luminosity, to such a degree that connecting it to an analogue Leica M camera - for example a Leica M6 - it would render a value of approximately 105 lines/mm in the center at f/2 using the traditional method of bar chart with resolution for center, border and corners at different f stops (the Summicron-M 50 mm f/2 reaches 64 lines/mm in the center at f/2) and low sensitiveness black and white 35 mm films like Adox CMS 20, Kodak Technical Pan 25 kept in fridge or Argenti Nanotomic-X ISO 32.
If we add to it the well-proven fact that this lens has already been tested attached to the Leica Monochrom (with exceptional results up to ISO 6400) and Leica M9 and M9-P (with top-notch results up to ISO 1250 and even iso 2500 with an accurate exposure as proved by Brian Bower), it seems apparent that both in the short and long term, the Apo-Summicron-M 50 mm f/2 ASPH will make up an unbeatable binomium with the highly advanced sensor of the future Leica M10 and the even better subsequent digital captors that could be included afterwards inside models of full frame digital Leicas M.
On the other hand, the remarkable proximity of lines with extremely high values for so great maximum diaphragm aperture depicted by the MTF curves of this lens, show that the bokeh has to be excellent.
In this regard, in my viewpoint, nobody should go mad with bokeh topic: obviously, the Apo-Summicron-M 50 mm f/2 ASPH won´t deliver a swirling bokeh comparable to the one rendered by the Noctilux-M 50 mm f/1, Summilux-M 75 mm f/1.4, Thambar 90 mm f/2 or Noct-Nikkor 58 mm f/1.2, unmatched lenses in this scope and greatly created with the adequate residual optical aberrations at full apertures to enable an exceedingly beautiful capture of the out of focus areas, or the one typical in Large Format lenses sporting a Petzval dseign, etc.
But it doesn´t matter at all. The MTF graphs of the Apo-Summicron-M 50 mm f/2 ASPH very clearly show that its bokeh must be superb and will flawlessly carry out its mission taking pictures at f/2 and f/2.8
All these data clearly indicate that already at full aperture f/2, the Apo-Summicron-M 50 mm f/2 ASPH achieves a top-notch reproduction of the extremely fine details of photographed subjects on the whole image surface, both in the center, borders and corners, with a gorgeous contours sharpness - from which it can be inferred a very good acutance - and contrast, with astigmatism and coma having been reduced to zero in the outer areas.
Besides, the average value of 65% between center, borders and corners obtained at the widest f/2 aperture by its continuous sagittal and discontinuous tangential lines of contrast and sharpness of fine details for 40 lp/mm is highly revealing.
On the other hand, considering the also astonishing mechanic building of this lens, it should feature an integral obliteration of any inner flare -however small it could be- shooting stopping down and an utter blockade of sun beams in borders and corners.
The more than remarkable proximity of the continuous and discontinuous lines at the four different values of the MTF Graph at such large f/2 aperture, hints at a reduction to 0 of astigmatism, along with a superb level of detail in shadows and absence of coma in the image areas with lights, specially in night photographs.
The aforementioned work by Brian Bower includes a special appendix on the Leica M9, and from a global viewpoint it is prominent in its superb photographic and text quality, where he insists on the immense future chances of the Leica M Digital System and its aspheric lenses in different focal lengths, whose practical use in a number of photographic environments (along with very useful advice on photography using every Leica M aspheric lens between 17 mm and 135 mm, techniques of flash using, how to use a wide range of accessories, viewfinder magnifiers, macro adapters, etc) he explains masterfully.
The introduction of the Apo-Summicron-M 50 mm f/2 ASPH (which - together with the rest of highly luminous aspheric Leica M lenses featuring unmatched optical and mechanical quality currently in existence - will splendidly synergize with the higher performance color digital sensors and DSPs which will appear in forthcoming years), has enhanced even more the greatly visionary nature of his confidence in the Leica M Digital System, nowadays with difference the one delivering the highest optical and mechanical quality among the ones belonging to the exclusive sphere of very small and light cameras, in perfect simbiosis with lenses miniaturized to the highest possible degree and very light for its format. Photo: José Manuel Serrano Esparza
APO-SUMMICRON-M 50 MM F/2 ASPH AT F/2.8
But what happens between 18 mm (border of the image) and 21 mm (corner of the image) is an even greater feat, since the discontinuous tangential red line of contrast for 5 lp/mm keeps practically at the same height as in image center (0 of the lower scale) with an almost imperceptible drop to 97% , while the continuous sagittal red line of contrast for 5 lp/mm that has also kept its value at the same height practically until arriving at 18 mm from the image center, begins from this spot onwards a little progressive descent resulting in a value of 96% at 20 mm from the image center and 95% at 21 mm - on the very corner- from image center.
These are with great difference the best values of for 5 lp/mm lines of contrast delivered hitherto by a 50 mm lens at f/2.8, with an astonishing evenness of performance, practically identical, both in the center (0 of the Y´ horizontal scale in mm), borders (18 in the horizontal scale) and corners (21 in the horizontal scale).
In both lines of contrast for 5 lp/mm at f/2.8, the Apo-Summicron-M 50 mm f/2 ASPH
It must be underlined that Mandler´s Summicron-M 50 mm f/2 Versions 4 and 5, though being beaten in contrast quality by the new Apo-Summicron-M 50 mm f/2 ASPH at f/2.8 (in a less overwhelming way than at f/2) features a fabulous contrast turning it into a very high performance lens even currently, 33 years after its design, which says a lot for Walter Mandler, who also reduced the production cost not only without dropping the quality but slightly improving it.
If the comparison is made to the Summilux-M 50 mm f/1,4 ASPH (which goes on being with difference the best 50 mm f/1.4 lens ever) at f/2.8,
The Summilux-M 50 mm f/1.4 ASPH at f/2 at f/2.8 is beaten by the Apo-Summicron-M 50 mm f/2 ASPH at f/2.8 after a very tough fight, which proves that the Summilux-M 50 mm f/1.4 ASPH is an absolutely exceptional highly luminous lens also delivering a stratospheric performance in center, borders and corners.
Evidently, the Apo-Summicron-M 50 mm f/2 ASPH betters it in both lines for 5 lp/mm, very slightly in center and borders and with some more difference on the corner, but it must be borne in mind that the Summilux-M 50 mm f/1.4 ASPH is an optical design featuring one f stop more of maximum luminosity, and when doubling the speed of a lens, the designer must control four times as many aberrations and often even more.
On the other hand, in my viewpoint the two different solutions adopted in each of these lenses to achieve the maximum feasible uniformity of exceptional optical performance in center, borders and corners at f/2.8 are hugely interesting: in the Apo-Summicron-M 50 mm f/2 ASPH at f/2.8, the presentation of credentials is incontestable: maximum height and joint of both lines for 5 lp/mm in the MTF graph, which advance practically overlapped and unaltered up to the border of the image, with a very slight quality descent on the very corner, where the continuous sagittal line for 5 lp/mm doesn´t drop under 94.7 % and the discontinuous tangential line for 5 lp/mm reaches a value of 97%, very similar to the one obtained in the center.
But albeit the two lines for 5 lp/mm of the Summilux-M 50 mm f/1.4 ASPH at f/2.8 aren´t so greatly joint to the extent of superposing up to practically the border of the image, they show some impressive achievements, because on searching also for the maximum feasible top-notch quality uniformity in center, border and corners, the values at 5 mm (98.5%), 10 mm (98.4%), 15 mm (98.5 %) and 16 mm (98.6%, superating near the border of the image the performance in the center) of the continuous sagittal red line for 5 lp/mm are a true optical exploit.
The continuous sagittal red line for 10 lp/mm (the second one starting from top of the MTF graph) displays cum laude values too: it reaches a value of 97% in the center, which keeps on absolutely unaltered up to 7 mm from the center of the image, dropping in an almost imperceptible way to 96.5 % at 9 mm from the image center, and goes on with its very slight fall until reaching a value of 95.6% at 12 mm from the center and 95% at 15 mm from the center, a point from which it experiences a very moderate descent until reaching a value of 93% at 18 mm - already in the border- of the image center, and from here onwards, a physically unavoidable more pronounced fall takes place until getting a value of 92% at 20 mm from the center and 83% at 21 mm - on the very corner- from image center.
Furthermore, in a great effort looking for the maximum possible evenness of optical performance, from a distance of 13.5 mm to the center of the image, the discontinuous tangential red line of contrast for 10 lp/mm develops a commendable slight increase, with a value of 96%, which continues up to 18 mm from the image center (in this stretch, such discontinuous line of contrast for 10 lp/mm follows its path going wholly parallel and very close to the discontinuous line for 5 lp/mm between 13.5 mm and 18 mm), falling very slightly from this spot and keeping a value of 96% up to the corner, where it drops very slightly up to 94.8%.
In both lines of contrast for 10 lp/mm at f/2.8, the Apo-Summicron-M 50 mm f/2 ASPH
Likewise, in both lines of contrast for 10 lp/mm at f/2.8, the Apo-Summicron-M 50 mm f/2 ASPH
On its turn, the continuous sagittal red line for 20 lp/mm (the third one beginning from top of the MTF graph) indicating the resolution for the finest structures, starts with a superb value of 93% in the image center, which raises slightly and in a progressive way until reaching a value of 93.5% at 3 mm from the center, which even increases a bit at 4.5 mm from the image center (93.8%), point from which it descents very mildly till arriving at 6 mm from the image center, where it shows a value of 93.6%.
From this spot on, it experiences a moderate drop until arriving at a distance of 9 mm from the image center, with a value of 91. 5% and keeps on going down in a somewhat more pronounced way (but still keeping an excellent quality) until arriving at 10.5 mm from the image center (with a value of 90%) and at 12 mm from the center (with a value of 88.5%).
From here on, there´s a tremendous effort striving after getting maximum resolving power uniformity, and though the continuous sagittal red line for 20 lp/mm goes on falling, it does it between 12 mm from the center and 15 mm from the center (with a value of 87%), in a much more moderate way than between 9 mm and 12 mm from the image center, keeping the strenuous effort up to 16.5 mm from image center (with a value of 86%) in order to delay the inevitable fall near the border of the image, which nevertheless, goes on delivering top-notch values of 82% at 18 mm from the center, 75% at 19.5 mm from the center and nothing less than a 67% at 21 mm from the image center, already on the very corner.
But the behaviour of the discontinuous tangential red line of for 20 lp/mm is even more amazing, exhibiting an incredible evenness of optical performance (now regarding resolving power) obtained by this new Leica 50 mm flagship, since it begins its path with a value of 93% in the image center, superposing almost utterly with the continuous sagittal line for 20 lp/mm until arriving at 3 mm from image center, where it gets a value of 93.1%, sharing values greatly approaching to the ones rendered by the continuous sagittal red line for 20 lp/mm between 3 mm and 12 mm from the image center, a stretch in which both lines show a huge proximity (to such an extent that they´re about to superpose between 3 mm and 9 mm and superpose between 9 mm and 11 mm, while between 11 mm and 12 mm they are almost joint).
From this point onwards, between 12 mm (value of 88.5%) and 15 mm (value of 90%) from the image center, the discontinuous red line for 20 lp/mm increases its performance, which maintains in an uninterrupted way not only up to 18 mm from the image center (already in the border, with a value of 90.1 %, which is a great achievement), but also up to 20 mm from the image center (on a spot very near the corner, where it beats very slightly the value of 90.1 % at 18 mm from the center, with a value of 90.2 %), something really astounding, bearing in mind a practically negligible drop at 21 mm (full corner) from the image center, with a value of 89.6%.
In both lines for 20 lp/mm at f/2.8, the Apo-Summicron-M 50 mm f/2 ASPH
And though with a narrower margin of difference, in both lines for 20 lp/mm at f/2.8, the Apo-Summicron-M 50 mm f/2 ASPH at f/2.8
In regard to the continuous sagittal red line for 40 lp/mm (the fourth one beginning from top) indicating the resolution of the finest structures, the Apo-Summicron-M 50 mm f/2 ASPH obtains an impressive value of 80.5 % in the image center (0 of the horizontal Y´ scale in mm), which in a highly praiseworthy way progressively raises its quality from a distance of 1 mm to the image center (value of 81%), getting a value of 82% at 3 mm from the image center and reaching its peak at 4.5 mm from the center, point from which its descends slightly, attaining a value of 81% at 6 mm from image center and 80% at 7 mm from the center, a spot from which the fall is more pronounced, reaching a value of 70% at 10.5 mm from image center, 64% at 12 mm from the center and 62 % at 14 mm from image center, starting from here a balancing increase of quality that gets a value of 62.5% at a distance of 15 mm from center and goes on up to 16.5 mm from the center (value of 63%), which descends only very slightly at 18 mm -border of the image- from the center (with an exceptional value of 62%), at 18.8 mm from the center (value of 60%), 58% at 20 mm from the center and 57% at 21 mm from the center (in full corner).
On its turn, the discontinuous tangential red line for 40 lp/mm also indicating the resolution of the finest structures, begins with a superb value of 80.5% in the center of the image, and superposes with the continuous sagittal red line for 40 lp/mm up to 1.5 mm from the center, a point from which it follows its path going very slightly under the continuous tangential red line for 40 lp/mm, describing a practically straight trajectory (81.2% at 3 mm from the center and 79.8% at 4.5 mm from the center), until arriving at 5.8 mm from the image center (with a value of 79.5%), where it begins a slight drop, reaching a value of 73% at 10.5 mm from image center and 71% at 12 mm from image center, obtaining a value of 69% at 12.6 mm from the center, spot from which (in a new exceedingly strenuous effort looking for maximum balance in performance between center, borders and corners) starts an outstanding remounting, attaining a value of 72% at 14 mm from the center and 73% at 15 mm from the center, keeping on the quality soaring until reaching a distance of 16.5 mm from image center, where it gets a value of 75%, peak which even raises slightly on arriving at 18 mm from the center (already in the border of the image), where it gets a value of 76%, identical to the one obtained at 9 mm from image center, keeping this value until nothing less than 19.5 mm from image center, with a very slight descent (with a value of 74%) in full corner, at 21 mm from image center.
This evenness of top-notch performance between the discontinuous tangential red line for 40 lp/mm between 16.5 mm and 21 mm from image center is a top-drawer optical feat.
In both lines for 40 lp/mm at f/2.8, the Apo-Summicron-m 50 mm f/2 ASPH
And such as could be expected, the Apo-Summicron-M 50 mm f/2 ASPH at f/2.8
It must be highlighted the fact that Summicron-M 50 mm f/2 in versions 4 and 5 designed by Walter Mandler (who gave top priority to the optical calculum in order to achieve a global balance of image more biased to the center, thanks to his exceedingly deep knowledge of materials that made him opt for the manufacturing of the two last back elements with special optical glasses boasting a high refractive index) with its value of continuous sagittal line of 67% in the center for 40 lp/mm also beats slightly the continuous sagittal line for 40 lp/mm of the Summilux-M 50 mm f/1.4 ASPH, which gets a value of 63% in the center, which speaks very well about Walter Mandler´s design, built without aspheric surfaces or floating elements and conceived in 1979, 33 years ago.
On its turn, the tangential discontinuous red line for 40 lp/mm of the Apo-Summicron-M 50 mm f/2 ASPH delivers an optical performance far superior to Mandler´s Summicron-M 50 mm f/2 and the Summilux-M 50 mm f/1.4 ASPH, reaching in the image center a value of 80.5 % (67% the Summicron-M 50 mm f/2 and a 63% the Summilux-M 50 mm f/1.4 ASPH), 76% in the border (28.5% the Summicron-M 50 mm f/2 and a 50% the Summilux-M 50 mm f/1.4 ASPH) and 74% in the corner (22% the Summicron-M 50 mm f/2 and 28% the Summilux-M 50 mm f/1.4 ASPH).
All these data clearly show that the improvement in image quality in the Apo-Summicron-M 50 mm f/2 ASPH from f/2 (already superb) to f/2.8 is very small, barely perceptible in practice in the center of the image, even in big enlargements, and in my viewpoint such very little betterment will be only discernible by an expert in the borders and corners of big copies on photographic paper from 15 x 20 inches upwards, going unnoticed for most observers, even at the nearest watching distances.
The impressive joint and proximity of the continuous and discontinuous lines in four values (5, 10, 20 and 40 lp/mm) indicate that astigmatism has completely been obliterated.
APO-SUMMICRON-M 50 MM F/2 ASPH AT F/5.6
Moreover, unlike the Apo-Summicron-R 100 mm f/2.8 at f/5.6, in the Apo-Summicron-M 50 mm f/2 ASPH it has been wiped out the exceedingly strong and until very recently inevitable bias to the development of a pronounced bulge on the central right area of the pair of continuous sagittal and discontinuous tangential red lines for 40 lp/mm (observable in the Apo-Elmarit-R 100 mm f/2.8 at f/5.6, above all between 5 mm and 17.5 mm from the image center), as a consequence of the Blendendifferenz (focus shift).
This way, though it may seem incredible, the optical designer has been able to achieve in the Apo-Summicron-M 50 ASPH a much higher straightness and joint of both lines of resolution for 20 lp/mm and very specially for 40 lp/mm than in the Apo-Summicron-R 100 mm f/2.8, finding solutions to reduce the Blendendifferenz to negligible levels on stopping down, without any drop in contrast quality.
On the other hand, if the results obtained by the Apo-Summicron-M 50 mm f/2 ASPH at f/2 and f/2.8 beat with huge difference in center, borders and corners to all the 50 mm lenses made in the world till now, at f/5.6 the quality parameters reached on the 100% of the image surface are the scientific benchmark peak ever achieved with a 50 mm lens in the whole history of physics and optics.
The continuous sagittal red line of contrast for 5 lp/mm at f/5.6 (the first one beginning from top of the graph) shows an incredible evenness of performance, in such a way that it starts with a value of 98% in the center of the image (very slightly inferior -because of the diffraction which begins appearing- to the center, although it goes on being a stratospheric value), which it keeps practically unaltered up to 15 mm from the image center.
And what happens subsequently is truly amazing, because from 15 mm from the image center onwards, there´s a slight quality increase with respect to the center, getting a value of 98.3 % in the border (id est, at 18 mm from the center) and from here, a very slight fall making that between 18.1 mm and 21 mm from the image center, a value of 98%, identical to the one attained in the center, is achieved !
In my viewpoint, this fact makes up an unparalleled feat throughout the history of photographic 50 mm lenses, with a clear quality priority for maximum possible uniformity of optical performance between center (0 of the horizontal Y´ mm axis) and corner (21 mm from that horizontal axis), while in all of the standard 50 mm (and other focal length lenses) built until now, the performance in borders and above all corners, is inferior to the one obtained in the center.
This fact makes up an unprecedented feat in the whole history of 50 mm lenses, with a clear quality priority of maximum possible performance between center (0 of the horizontal Y´ mm) and corner (21 mm of such horizontal axis), when in all the standard 50 mm focal length lenses (and in other different focal length objectives) built hitherto, performance in borders and above all in corners is lower than in the center.
But this concept doesn´t almost exist in the Apo-Summicron-M 50 mm f/2 ASPH, whose huge optical and mechanical potential allows to get pictures featuring an identical extraordinary quality - something unknown hitherto- both in the center, borders and corners, to such an extent that the exceptional quality level of 98% reached by the continuous sagittal line of contrast for 5 lp/mm in the center of the image, is slightly beaten in its border (value of 98.3%) and equalled in the corner (value of 98%).
It´s true that because of the beginning of diffraction, the quality in the center for 5 lp/mm at f/5.6 drops very slightly to a value of 98% (it isn´t detectable in practice) when compared to f/2.8, (a diaphragm in which the image center attains its maximum peak with a value of 98.5%), but it doesn´t matter at all, since the values go on being stratospheric and above all practically identical both in the center, borders and extreme corners, however incredible it may seem, with the continuous sagittal red line of contrast for 5 lp/mm advancing utterly straight and parallel to the upper limit of the MTF graph.
On its turn, the discontinuous red line of contrast for 5 lp/mm at f/5.6 exhibits a practically identical behaviour, advancing in an utterly superposed way (which clearly indicates the impressive contrast) with the continuous red line of contrast for 5 lp/mm, from the image center to the very corner, with a superb average value of 98%.
In both lines for 5 lp/mm, the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6
On the other hand, the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6
It proves the likewise stratospheric potential of the Summilux-M 50 mm f/1.4 ASPH, whose continuous sagittal red line of contrast for f/5.6 equals the one described by the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6, betters very slightly in the border to the Apo-Summicron 50 ASPH and is only beaten at f/5.6 in the corner by the Apo-Summicron 50 mm f/2 ASPH, whose uniformity of performance between center, border and the very corner greatly approaches to 100% for the first time in the history of photography in a 50 mm lens for full frame 24 x 36 mm cameras; while the discontinuous tangential red line for 5 lp/mm at f/5.6 of the Summilux-M 50 mm f/1.4 ASPH at f/5.6 gets a value of 98% in the center (identical to the one rendered by the Apo-Summicron-M 50 ASPH), 97.7% in the border (98.3 % the Apo-Summicron 50 ASPH) and 93% in the corner (98% in the Apo-Summicron 50 ASPH).
The continuous sagittal red line of contrast for 10 lp/mm (the second one beginning from top of the MTF graph) also reveals exceptional results, both in the center, borders and corners: it starts with an incontestable value of 96% in the image center, which keeps on identical up to 3 mm from the center, and from this point onwards, it experiences a very slight increase, until arriving at 6 mm from the image center, where it gets a value of 95.7 % at 12 mm from the image center and 95.2 % at 15 mm from the center, but from this spot onwards, the titanic effort made by the designer looking for maximum feasible evenness of extraordinary performance on the whole surface of the image, which makes up the most distinctive hallmark of the Apo-Summicron-M 50 mm f/2 ASPH, appears again, and the continuous red line of contrast for 10 lp/mm raises slightly until reaching 18 mm from image center (already in the border) with an identical value to the one rendered at 21 mm from the image center !
And if it were not enough, at 19 mm from the center (an even closer to the corner spot), there´s an astounding very slight increase of contrast quality, which reaches a value of 96.1% at 19 mm from the center, and keeps on intact up to the corner itself, at 21 mm from the image center !
On its turn, the discontinuous tangential red line of contrast for 10 lp/mm shows an exceptional behaviour, reaching an average value of 96%, practically equal to the one delivered by the continuous sagittal red line of contrast for 10 lp/mm, with which it superposes almost at 100% during its entire path, from center to border, with a slight descent at 21 mm from the image center, already in full corner, where it gets a value of 94.5 %.
In both lines of contrast for 10 lp/mm, the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6
On the other hand, in both lines of contrast for 10 lp/mm at f/5.6, the Apo-Summicron-M 50 mm f/2 ASPH
The continuous sagittal red line for 20 lp/mm (the third one beginning from top of the MTF graph) indicating the resolution of the finest structures, starts with a superb value of 90% in the image center (0 of the horizontal Y´ mm scale), which ascends slightly until arriving at a distance of 3 mm from the center, where it gets a value of 90.5%, point from which it goes on its quality increase until arriving at 6 mm from image center, where it attains a value of 92%, which it keeps in an almost integral way until arriving at 9 mm from the center. From here onwards, there´s a progressive mild fall, getting a value of 91% at 12 mm from the center and 89% at 15 mm from the center, and what happens from this spot (very close to the image border) onwards, can only be described as exceptional, since the continuous red line for 20 lp/mm raises its level of quality until arriving at 18 mm from the image center (already in the border ), where its achieves a value of 90%, the same as the one delivered in the image center !
If this means by itself a highly outstanding optical exploit, it isn´t less true that it precedes to something even more amzaing and exceedingly difficult to achieve: at a distance of 18 mm from the image center, the continuous sagittal red line for 20 lp/mm, experiences a new increase of quality until arriving at 20 mm from the center and at 21 mm from the center (already in full corner), attaining in both spots a stratospheric value of 91%, slightly superior to the one rendered in the center of the image !!!
Needless to say that this continuous sagittal red line for 20 lp/mm undoubtedly proves that the Apo-Summicron-M 50 mm f/2 ASPH is with difference the 50 mm lens delivering the highest resolving power ever made in the world, but in my viewpoint, it´s equally or even more relevant (above all to practical photographic purposes) the incredible homogeneity of exceedingly high quality of results in center, borders and corners, in such a way that very probably it will be able to reach approximately 120 lines / mm in the center, borders and corners of the image shooting with a 35 mm analogue Leica camera and high resolving power black and white film like Adox CMS 20 or Argenti nanotomic-X ISO 32 on a tripod at f/5.6
The new flagship of Leica in the 50 mm standard focal length represents the optical and mechanical apex of quality reached throughout 91 years of evolution after Professor Max Berek calculated in Wetzlar in 1921
the optical formula of the Leitz Elmax 50 mm f/3.5 featuring five elements (based on the Cooke Triplet scheme and including an essential configuration convex lens/concave lens/convex lens optimized for relatively moderate apertures) firstly coupled to the Leica ´0´ between 1923 and 1924 (being called Anastigmat instead of Elmax, though both of them were an identical design) and later to the Leica 1 (Model A) between 1924 and 1925.
On its turn, the discontinuous tangential red line for 20 lp/mm of the Apo-Summicron-M 50 mm f/2 ASPH also exhibits an exceptional level of quality: it begins with a value of 90.5% in the image center and superposes practically in an integral way with the continuous red line for 20 lp/mm up to 3 mm from image center, point from which it starts a slight descent, following its path slightly under the continuous sagittal red line for 20 lp/mm and in a parallel way to it until arriving at 9 mm from the image center, where it gets a value of 89%. From this spot onwards, the very slight drop of quality keeps on until arriving at 12 mm from image center, point in which it reaches a value of 88.6 %. From here, begins to happen a bit more evident fall (but still very restrained and with excellent values, because it is the area near the image border), getting a value of 87.5% at 15 mm from the image center and 86.5% at 18 mm from the image center (already in full border).
From this spot onwards, once more, there´s a very strenuous effort in search for maximum feasible uniformity of optical performance between center, borders and corners, in such a way that at a distance of 18 mm from the image center, the designer manages to hold back the progressive descent which has been taking place from 9 mm from the image center, and a value of discontinuous tangential red line for 20 lp/mm of 86.5 % in the border (at a distance of 18 mm from image center) is kept up to 20.5 mm from the center, which is an impresive breakthrough, underlined by the fact that on the very corner, at 21 mm from the image center, the inevitable fall is practically negligible, with a value of 86.3%, something that really deserves accolades.
The proximity between both lines -superposing each other up to 3 mm from the image center- is huge, and with difference the greatest jointness hitherto for a 50 mm lens at f/5.6 between the continuous sagittal red line for 20 lp/mm at f/5.6 and the discontinuous tangential red line for 20 lp/mm.
In both lines of resolution for 20 lp/mm at f/5.6, the Apo-Summicron-M 50 mm f/2 ASPH
On the other hand, the Apo-Summicron-M 50 mm f/2 ASPH
The continuous sagittal red line for 40 lp/mm which also indicates the resolution for the finest structures, likewise shows a great level, starting with a value of 78% in the center, which is kept up to a distance of 1 mm from the image center, point from which there´s a progressive increase that reaches a value of 79.5% at 3 mm from the center and 82 % at a distance of 6 mm from the center. Shortly after, the sagittal red line for 40 lp/mm reaches its maximum peak at a distance of 7 mm from the image center, with a value of 83%, beginning a very slight descent until arriving at 9 mm from the image center, with a value of 82.1 %, spot from which there´s a more visible drop (but still very restrained) that obtains a value of 80% at 11 mm from image center and 78.5 % at 12 mm from the center, with the slight descent following its trajectory until arriving at 13.5 mm from the center (value of 77%) and at 15 mm from the center, where it gets a value of 76%, arriving at its lowest spot at 15.5 mm from the image center, with a value of 75.6% , point from which arises a very commendable and progressive quality ascent looking for the maximum possible homogeneity of performance between center, borders and corners, in such a way that at 18 mm from the image center (that´s to say, in the border), it attains a value of 76.2 %, and from this spot onwards, it goes on rising in an even more visible manner until arriving at 20.5 mm from the image center, where it gets a value of 78.5% (slightly higher than the value of 78% in the image center and identical to the one rendered at 12 mm from the center) which it holds unchanged until arriving at a distance of 21 mm from the image center, on the very corner of the image.
On its turn, the discontinuous tangential red line for 40 lp/mm also shows an exceptional level, being at every moment very near the continuous sagittal red line for 40 lp/mm, above all in the center, border surroundings and corners.
It begins with a value of 78% in the image center, superposing with the continuous tangential red line for 40 lp/mm up to 2 mm from the center, spot from which it starts a slight progressive descent, until arriving at a distance of 6 mm from the image center, where it obtains a value of 77%. From here onwards, the small gradual slope continues in a bit more pronounced way (but very contained and still boasting excellent quality levels of sharpness), in such a way that at 9 mm from the image center, it reaches a value of 76% and at 12 mm from the center its value is 75%. From this point up to the border of the image, the drop is a little more evident (but still delivering a great level, since it nevers falls under 72%), attaining a value of 73.5% at 15 mm from the image center, 73% at 16.5 mm from the center and 72% at 18 mm from the center (id est, in the border of the image), spot from which there´s a very praiseworthy quality increase in resolving power, which gets a value of 73.9% at 20.5 mm from the image center (on a point hugely close to the corner) and 72.5% at 21 mm from the image center (that´s to say, on the corner itself), where it slightly beats the value obtained in the border.
Needless to say that the microcontrast capturing power of this optical jewel is huge, reaching in this side unheard-of levels of quality in the scope of 50 mm lenses for full frame 24 x 36 mm format.
In both lines for 40 lp/mm at f/5.6, the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6
Likewise, in both lines for 40 lp/mm at f/5.6, the Apo-Summicron-M 50 mm f/2 ASPH
Even more amazing (with the huge optical tour de force that it implies, since the shorter the focal length of a lens, the greater become the designing difficulties when trying to correct borders and corners, which increase in a geometrical proportion) is to realize that the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6
Differences are even more significant in the continuous and discontinuous lines of resolution for 40 lp/mm: the continuous sagittal line of resolution for 40 lp/mm of the Apo-Summicron-M 90 mm f/2 ASPH at f/5.6 obtains in the center a value of 72.5% (78% the Apo-Summicron 50 ASPH), 72% in the border (76.2% the Apo-Summicron 50 ASPH) and 71.8% in the corner (78.5% the Apo-Summicron 50 ASPH); while the discontinuous tangential red line for 40 lp/mm of the Apo-Summicron-M 90 mm f/2 ASPH at f/5.6 gets in the center a value of 72.5% (78% the Apo-Summicron 50 ASPH), 72% in the border (72% the Apo-Summicron 50 ASPH) and 71.75 in the corner (72.5% the Apo-Summicron 50 ASPH), but because of the Blendendifferenz (focus shift) generated by the beginning of diffraction at f/5.6 - only the cream of the cream of lenses start their diffraction at this f stop- the joint of both lines for 40 lp/mm in the Apo-Summicron-M 90 mm f/2 ASPH, though being within extraordinary parameters of quality, is clearly inferior (above all between 5 and 15 mm from image center) to the Apo-Summicron 50 ASPH), whose proximity of lines and uniformity of optical performance between center, borders and corners is evidently superior, oscillating between values of 78% and 72.5%.
All these data clearly indicate that the image quality achieved by the Apo-Summicron-M 50 mm f/2 ASPH at f/5.6 is simply stratospheric, with cum laude values on the whole image surface, both for the continuous sagittal and discontinuous tangential lines of contrast for 5 lp/mm and 10 lp/mm (with exceedingly high values, superposing each other at every moment until arriving at 18 mm from image center - id est, borders - and about to superpose between borders and corners) and also for the continuous sagittal and discontinuous tangential lines of resolution of fine details for 20 lp/mm and 40 lp/mm.
The also stratospheric joint of continuous and discontinuous lines (two of which - 5 lp/mm and 10 lp/mm - advance totally superposed from center to borders, going parallel to the upper limit of the MTF graph) at the four different values (5 lp/mm, 10 lp/mm, 20 lp/mm and 40 lp/mm) indicate a total elimination of astigmatism.
Moreover, a further optical feat has been accomplished: to greatly beat (with 16 mm less of focal length) the tremendous resolving power delivered by the secret prototype Elcan 66 mm f/2 designed by Walter Mandler and manufactured by Leitz Midland, Ontario (Canadá) in 1970 for the U.S Navy, perhaps the M mount Leica lens featuring the biggest balance between maximum possible sharpness and capturing of details, correction of aberrations and use of different optical glasses made until the appearance of the Apo-Summicron-M 50 mm f/2 ASPH, which is with difference the 50 mm lens built hitherto rendering the greatest resolving power, with an incredible sharpness and capturing of the most extremely fine microcontrast structures and hidden details.
DISTORTION
Exceedingly well corrected, 0.40 % pincushion, not visible in practice and very slightly better in this regard than Walter Mandler´s Summicron-M 50 mm f/2 Versions 4 and 5 (0.47% - it must be kept in mind that this lens has been and goes on being considered since its creation in 1979 one of the three undisputed world benchmark 50 mm objectives as to distortion-) and also beating through an exceedingly narrow margin the Summilux-M 50 mm f/1.4 ASPH (whose distortion values oscillate between 0.42% at infinitum, 0.44% at 15 m and 0.46% at 4 m).
Therefore, the distortion graphs of the Apo-Summicron-M 50 mm f/2 ASPH, in the same way as happens with the rest of ultraluminous aspherical Leica M ASPH lenses, display superb results which are not product of a merging between lens + correction with software, but consequence of an impressive optical formula and tremendous mechanical accuracy of assembling of the glass elements and optical groups inside the lens barrel, together with a cutting-edge technology grinding and polishing on the tangentially oriented points of the aspherical surfaces, from border to center, along with a highly painstaking computerized and laser beam guided interferometric tracking, which can only be made by a very qualified technician featuring a lot of years of experience, without forgetting an incredibly precise centering with last generation CNC machines which are used after the high-end preliminary polishing and subsequent evaluation of all the optical elements one by one.
If we add to it the better and better full frame 24 x 36 digital sensors and DSPs used by Leica in its rangefinder series M 35 m cameras, we can properly understand the superb results achieved in large size copies on photographic paper, which are also a further keystone to verify the real image quality delivered by a lens.
VIGNETTING
Very slightly perceptible at f/2, negligible at f/2.8 and non existent from f/4 onwards.
CONCLUSION
The MTF curves of the Apo-Summicron-M 50 mm f/2 ASPH do undoubtedly prove that Peter Karbe has designed the best calculated and corrected 50 mm lens made in the world till now, optimized for the full format 24 x 36 mm state of the art sensor of the Leica M Monochrom camera and the one approaching more to the nonexistent 100% perfect lens, greatly challenging and going beyond the classic axiom stating that the image quality delivered by a lens isn´t equal on the whole area of the coverage circle of the film or digital sensor and the illumination, resolution and contrast drop from center to border of the circle.
To properly gain insight into the brutal magnitude of the unprecedented optical tour de force which has meant the design and manufactureing of this standard 50 mm lens, suffice it to say that it holds inside its barrel configurations of optical elements and a handcrafted mechanical construction inherent to several technological, physics and optical benchmark plateaus:
a) The Double-Gauss scheme lacking aspherical surfaces and floating elements of the Summicron-M 50 mm f/2, taken to its scientifically possible boundaries by Walter Mandler. The Apo-Summicron-M 50 mm f/2 ASPH includes three elements with clear Double-Gauss configuration, specially the first and third ones, improving the optical quality - with half the focal length and the huge difficulty of design it means on being more angular- of the two thick and independent elements of the back of the optical cell of the genuine six element Double-Gauss design Apo-Elmarit-R 100 mm f/2.8.
b) The scheme of Summilux-M 35 mm f/1.4 ASPH, featuring one aspheric element and three floating ones. The Apo-Summicron-M 50 mm f/2 ASPH includes an aspherical element, the closest to the diaphragm and located behind it, which has required an extraordinary precision of grinding and polishing with special CNC machines and greatly handcrafted parameters of manufacturing, with a very high rate of rejected units until getting the optimal ones, for the quality controls in every aspect of the Apo-Summicron-M 50 mm f/2 ASPH has been of extreme thoroughness.
c) The elite mechanic building made by Andre de Winter (Director of Mechanic Design of CW Sonderoptic Wetzlar, having previously also been Head of the Optomechanical Department of Leica Camera AG in Solms, and Optomechanical Designer of Leitz Canada Ltd), whose tremendous accuracy of assembly of the optical elements inside the barrel and the sturdiness and duration of the noble metals used will enable (as usual with Leica M lenses) a hard professional use of the Apo-Summicron-M 50 mm f/2 ASPH throughout a lot of decades with identical performance.
It mustn´t be forgotten that Leica was the first photographic concern to tackle the subject of autofocus, specifically with the working prototype AF Leitz Correfot, during the Photokina Köln 1976 and 1978, but in early eighties, it wisely decided not to follow that research field, since the amazing mechanical quality of its lenses is based on extremely stringent assembling tolerances that wouldn´t be feasible with the AF engines of autofocus systems, in spite of the outstanding breakthroughs made in the reflex domain specially by Canon and its USM ultrasonic motors and similar systems from other brands, which have enabled the installation in medium and large size lenses of a hugely fast and silent autofocus module circling the optical cell without adding much to diameter, and whose working core is an undulation in the piezo-electric element transferred to a rotor which subsequently turns the focusing ring.
d) An exceptional centering of the optical cell, which is vital to optimize performance.
e) A highly updated state-of-the-art blank-pressed asphere technology applied to the aspherical element of the Apo-Summicron-M 50 mm f/2 ASPH, located just behind the diaphragm.
f) A highly advanced program of optical correction analysis, making up an evolutive step beyond the updatings of COMO Program of Optical Correction (made from late eighties and nineties by Wolfgang Vollrath in Leitz Midland, Ontario and by Sigrun Kammans and Michael Heiden in Solms) and of Horst Schröder´s Analysis 01 Program, which along with Peter Karbe´s huge experience and intuition using the program in the adequate direction, has been fundamental for the genesis of the Apo-Summicron-M 50 mm f/2 ASPH, since the resolving power and capturing of details achieved across the entire imaging plane, both in the center, borders and corners, is exceptional and boasting an incredible homogeneity, which is a remarkable milestone, because during the designing stage, the more the lines of the MTF graph advance to the right, the more geometrically increases the lens bias to render those details with less accuracy, something which is not possible to avoid using only the automatic computerized optimization of optical correction, so working at this level it´s utterly indispensable to go far beyond, and the designer´s personal touches, a slew of tricks and paths and experience will become the key factor for a really unmatched performance.
g) The Leica full-fledged true apochromatic correction. Until very recently, it was thought that it was virtually impossible to beat both the apochromatic quality obtained by extraordinary M series aspherical lenses like the Apo-Summicron-M 75 mm f/2 ASPH, the Apo-Summicron-M 90 mm f/2 ASPH and the one delivered by legendary apochromatic Leica R series like the Apo-Elmarit-R 100 mm f/2.8, the Apo-Summicron-R 90 mm f/2 ASPH, the Apo-Summicron-R 180 mm f/2 and the Apo-Telyt-R 280 mm f/4.
But the Apo-Summicron-M 50 mm f/2 ASPH beats them (though through a narrow margin) in this side, which has an unutterable merit, since managing to better in apochromatic quality to lenses featuring double, triple or quadruple focal length (and which are within the cream of the crop of Leica lenses for full frame 24 x 36 mm cameras) is a quantum leap, even more relevant if we bear in mind that until very recently, to design a truly apochromatic lens (with the level of real apo correction achieved by Leica) featuring a 50 mm focal length was rather a dream.
As a matter of fact, even the two best 50 mm f/2 lenses in the world till May 10, 2012, the Summicron-M 50 mm f/2 and the Carl Zeiss Jena 50 mm f/2 ZM aren´t apochromatic, because they don´t need it to get an excellent optical performance and image quality, since achromatic correction is enough with lenses sporting standard or wideangle focal lengths, choosing the adequate optical glasses and combination of elements for each focal length, making the blue and green components of a light ray converge on the image plane, while for 75 mm or higher focal length lenses, the residual chromatic aberration of the non corrected red component of the entering light is much more visible, so if you wish maximum feasible luminosity and image quality in these focal lengths, it´s necessary the apochromatic correction of the secondary spectrum, making it utterly converge on the image plane.
It must be added to all the previous aspects the fairly praiseworthy fact that the Apo-Summicron-M 50 mm f/2 ASPH not only boasts the best apochromatic correction of all the Leica lenses manufactured hitherto and a top-notch fulfilment of the convergence of three different wavelengths, but it also achieves a very laudable practically integral elimination of the inevitable residual aberrations brought about by the fact that for the other wavelengths exists a different focusing point, so the design work when tackling the secondary spectrum has had to be absolutely strenuous, in the same way as with the spherochomatism correction at the widest f/2 and f/2.8 apertures, a context of extreme difficulty, in which Leica has surpassed itself with this unique lens, reducing the secondary spectrum to negligible levels in the whole range of wavelengths of the visual band, including the widest f stops.
On the other hand, evidently, the Apo-Summicron-M 50 mm f/2 ASPH is a very expensive lens, though from the moment of its presentation, Leica received some scathing criticisms - in my opinion lacking ground - stating that the Apo-Summicron 50 ASPH was ´exceedingly expensive, with an unjustified price tag´.
Obviously, the price is steep. But things are not so simple and vast majority of the acrimonious criticism came from people who believe that the Apo-Summicron-M 50 mm f/2 ASPH is too pricey for a 50, without realizing that this Apo-Summicron 50 ASPH is probably the greatest optical and mechanical feat in the whole history of the photographic industry and it is light years ahead the rest of many existing excellent 50 mm lenses (with the only exception of the Summilux-M 50 mm f/1.4 ASPH, which is also beaten but not with so huge difference).
It is very important to have clear that Leica hasn´t put that price to this formidable lens to generate a very important margin of economical benefit with its selling, since it is simply impossible, because the manufacturing cost of this optical jewel is huge, as a matter of fact much higher than the rest of best 50 mm lenses currently available.
The Apo-Summicron-M 50 mm f/2 ASPH has been mainly created because of two reasons:
a) To get the most of the state-of-the-art sensor of the Leica M Monochrom.
b) To enhance even more the firm prestige, because the 50-58 mm lenses featuring high luminosities between f/1.2 and f/2 (the f/0.95 and f/1 designs are a world apart in themselves) have traditionally been the reference patron in which all the brands of the photographic sector have put all of their know-how and expertise when trying to attain maximum possible opto-mechanical quality, without forgetting the highly significant fact that many of the greatest photographers in history
(particularly in the sphere of photojournalism) have created a very important percentage of their images with 50 mm lenses (the classical focal length par excellence) and miniature 24 x 36 mm format cameras.
This way, the MTF curves of the new Apo-Summicron-M 50 mm f/2 ASPH prove that this just born world benchmark of quality in 50 mm focal length for 24 x 36 mm cameras, overwhelmingly beats (said with all respect) in top-notch optical and mechanical excellence to all the great 50 mm lenses of different brands made hitherto (except four, quoted in the beginning of this article and compared to which, though big, its superiority is not so huge as with regard to the rest of 50 mm lenses in existence).
By and large, to currently launch into market a 50 mm lens boasting so astounding capabilities is to all intents and purposes a very important challenge, because providing significant improvements in this so massively studied focal length (whose first historical international benchmarks of quality were Max Berek´s Elmar 5 cm f/3.5 in 1924 and Ludwig Bertele´s Carl Zeiss Jena Sonnar 5 cm f/1.5 in 1932) is something of the highest conceivable difficulty and not risk-free.
Probably, Leica was the only brand which could afford to manufacture a lens like this under the current worldwide economical context.
One of the most important reasons for the very high manufacturing cost of this lens is the exceedingly high rate of rejected optical elements when they don´t fulfill the hugely stringent Leica tolerance rates at this level, since the greater the optical and mechanical performance, the greater will have to be the accuracy with which its optical elements will have to be grinded, polished and multicoated (it can often take some days to configure each of them, so the rejection of elements brings about loss of time and delays the production capacity), in such a way that after the polishing of the optical elements, highly qualified experts of Leica featuring a lot of years of experience (another of the key factors for the great success of the German photographic firm in the digital market) inspect their surfaces with the help of a highly advanced helium-neon laser interferometer, checking if the optical elements show defects which can result in dwindling of performance in specific areas or errors produced by astigmatism.
There´s also a further scientifically very important factor for the steep production cost, which is that regarding the part of the Apo-Summicron-M 50 mm f/2 ASPH featuring Double-Gauss configuration (that´s to say, the elements 1, 2 and 3 located in front of the diaphragm), Peter Karbe has managed to achieve something considered to be impossible: to improve the maximum feasible quality parameters brought forward by Walter Mandler in his famous doctoral dissertation Über die Berechnung einfacher Gauss-Objektive at Giessen University in 1979, in which he fixed the physics and optical limit (above all regarding contrast and resolving power) that was possible to attain with a Double-Gauss design, and which was beaten between 1989 and 1991 by Peter Karbe during his project of imporvement of Mandler´s Summicron-M 50 mm f/2 Versions 4 and 5, being able to increase its contrast value for 40 lp/mm over 50% at f/2 on the whole image surface, and simultaneously also raising the ability of fine details and nuances capturing at such widest aperture, likewise solving the lack of suitability of highly refractive optical glasses to correct colour aberrations using special kinds of glasses featuring anomalous partial dispersion in the elements 1 and 2, almost keeping intact the very small size and exceedingly light weight of Mandler´s Summicron-M 50 mm f/2, with only 4mm more of focal length than it and an optical formula whose elements located in front of the diaphragm resembled the ones sported by Mandler´s Summicron-M 50 mm f/2, while the ones placed behind it would follow the scheme of the Summilux-M 35 mm f/1.4 Asph, reaching an amazing contrast value of 75% at 40 lp/mm in the image center and adjacent areas and more than 50% on the corners, supported by its great colour correction.
Such Project of Summicron-M 50 mm f/2 Version 6, featuring eight elements and developed by Peter Karbe between 1989 and 1993, was finally abandoned due to its very high production cost and lack of commercial feasibility, but I do believe that more than twenty years after, that study of possibility of creation of a Summicron-M 50 mm f/2 beating Walter Mandler´s design from 1979, has greatly been the base on which the new Apo-Summicron-M 50 mm f/2 ASPH has been created, and obviously it hasn´t been possible to apply in it the integral philosophy of cost reduction used by Walter Mandler on designing its 6 element Summicron-M 50 mm f/2 Versions 4 and 5 featuring identical optical formula (in which he avoided the use of the expensive LaK9 - replacing it by an exceedingly skillful combination of flint glass elements- ) and only two types of optical glasses, of which only one (with a refractive index of 1.8) was special and expensive, coming from the Leitz Glass Laboratory, while to achieve the exceptional performance in borders and corners of the Apo-Summicron-M 50 mm f/2 ASPH (practically identical to the one rendered in the image center at every f stop and focusing distance) it has been necessary to use the best of the best existing in the Leitz Glass Laboratory in each of the 8 elements, particularly in the aspheric surface, the two lenses featuring a high refractive index and the three ones made with anomalous chromatic dispersion glass, which is another seminal factor for the inevitable very high production cost of this lens.
Evidence clearly hint that with this new world flagship in 50 mm focal length, Leica has increased to the maximum its already known handcrafting parameters of manual manufacturing in all the stages and in each one of the optical and mechanical elements, from which it can be inferred that all the records as to tolerance limits, searching for the maximum feasible consistency and homogeneity of performance unit by unit, have been beaten.
It´s impossible that something like that hasn´t a very high price, because it is at present with difference the best 50 mm lens on earth and a new optical and mechanical plateau is born with it as a new technological breakthrough.
It´s above all a question of prestige well rooted both in the legendary halcyon days of the past,
the blossoming present, fully integrated in the digital market,
and the highly prospective upcoming times showing the maximum possible fitting to the better and better sensors featuring superior resolution and pixel density which may appear in the short, medium and long term, because the optical and mechanical excellence of its lenses bestows Leica a great confidence and security about its future in the photographic digital market, something of which the new Apo-Summicron-M 50 mm f/2 ASPH is a good example.
IMPORTANT CONSIDERATIONS
Whatever it may be, in my viewpoint, both to overesteem and underesteem the significance of the MTF curves is an error.
It shouldn´t be forgotten that the design of a high performance luminous photographic lens is greatly an exercise of application of exceedingly deep mathematical knowledge and very complex calculi, a difficulty that when referring to Leica M lenses increases in geometrical magnitude, since unlike the retrofocus designs, they are to simultaneously achieve the greatest scientifically possible optical and mechanical performance with dimensions, weight and front lens diameter miniaturized to the utmost to avoid the interference with the viewing field of the RF viewfinder and synergize with the great compacity of 24 x 36 mm format mirrorless cameras with rangefinder like the Leica M-9, M9-P or M Monochrom.
Therefore, the MTF curves of the Apo-Summicron-M 50 mm f/2 ASPH made by Leica, such as was previously commented, provide highly valuable information on resolving power, contrast, bokeh, correction of the chromatic aberrations and also the very important factor of evenness of exceptional optical performance at different f stops (including the widest ones) and on the entire image surface, both in the center, borders and corners, which indicates very faithfully the authentic potential of this extraordinary lens, whose real capacities go far beyond all the digital sensors currently available in the world and probably the ones featured by the best digital captors to be made during the next years.
Nevertheless, in spite of the undoubtable significance of the MTF curves (above all if they´re made with the exactness typical in the mythical German photographic firm), it is very important neither overestimate nor underestimate them and to keep in mind that even in the case of Leica, which is the photographic segment firm publishing the most complete and reliable MTF curves, as well as making other ones
also displaying remarkable rigour, professionalism, self-commitment and valuable information on a number of sides of optical performance of its lenses, it isn´t less true that in the real photograpphic contexts other so or even more important factors come into play, so in my standpoint it is very important to bear in mind the following essential considerations:
1) The focusing accuracy with the rangefinder of the person using the Apo-Summicron-M 50 mm f/2 ASPH will be the most seminal factor when trying to get maximum possible quality of image. Not everybody has the same experience and skill taking pictures with RF cameras, and the visual ability and focusing accuracy with the rangefinder is different in each person, particularly with the widest diaphragms.
2) In order to make the most of the exceptional image quality that this lens enables to achieve, it is necessary that the rangefinder of the camera is perfectly aligned, because logically, the most minimum focusing error will affect the final image quality, specially at the most luminous f stops, both in horizontal and vertical shots, albeit in my opinion, is in the latter ones where the potential risks could be higher, due to the special technique and grabbing way of the mirrorless with rangefinder Leica M cameras to make pictures in non horizontal photographs, so it´s advisable to have the Leica M digital camera checked for its RF at least once a year.
3) Lenses like the Summicron-M 50 mm f/2, Carl Zeiss Planar 50 mm f/2 ZM, not to say the Summilux-M 50 mm f/1.4 ASPH, feature such a huge quality potential that very rarely it will be reached in its peak levels by any photographer, because of the special technique and abundant experience required to be able to use them at full performance. If you wish to attain the maximum resolution and focusing precision feasible, a sturdy tripod should be used.
But rangefinder mirrorless cameras were created above all to shoot handheld without any trepidation, even under low light conditions and at very low shutter speeds, taking advantage of the mirror lack, so in photographic environments shooting handheld, the Apo-Summicron-M 50 mm f/2 ASPH will go on being the benchmark (with a superb homogeneity of optical performance between f/2 and f/5.6 on the whole image surface), but differences in quality will reduce in a significant way (specially in colour photography) when compared to the fabulous Summilux-M 50 mm f/1.4 ASPH, which is in my viewpoint the best possible choice in opto-mechanical quality/price ratio among the currently existent 50 mm lenses.
Nevertheless, it´s very important to keep in mind that the design and manufacturing of aspherical lenses by Leica Camera AG hasn´t got as primordial aim to create objectives whose technical tests provide excellent data, but at every moment the fundamental mission for which the lenses are made is for the generation of images of the highest feasible quality in real photographic contexts and assignments, and in this regard, the great mechanical quality (so or even more important with the elapse of years than the optical performance) is decisive, because it is eventually what enables an outstanding consistency of results throughout decades, including the intact preservation of the precision of focusing helicoids, diaphragm blades, etc.
But above all, it seems apparent that in real photographic situations, the optical and mechanical performance of the Apo-Summicron-m 50 mm f/2 ASPH will be superb, whenever it is handled by professional photographers or advanced connoisseurs knowing what they are doing (obviously, because of its very high price tag and capacities it is a very special lens), because if the picture is not good, it makes no odds the camera and lens used, since neither the best camera nor the best lens make the photographer, and to all intents and purposes, the most significant factor to get a good picture is the person handling the camera and the attached lens.
It is also true that when taking pictures under conditions that are not absolutely optimal and controlled on a sturdy tripod, it won´t be possible to reach the full potential of the Apo-Summicron-M 50 mm f/2 ASPH, in the same way as happens with the Summilux-M 50 mm f/1.4 ASPH, and that the photograph itself is with difference the most important thing and not the technical sides of it.
But in my viewpoint, aside from the tremendous image quality attainable with the Apo-Summicron-M 50 mm f/2 ASPH, specially in terms of resolving power and contrast, its most significant feature is that whatever you get both shooting handheld, with a monopod or a sturdy tripod, for the first time in history, it will be almost identical in center, borders and extreme corners.
Anyway, it seems clear that the new Leica M benchmark of optical and mechanical quality in 50 mm focal length, featuring true apochromatic correction (an impressive technological breakthrough for such a short focal length) can be a great photographic tool in a wide variety of photographic genres (photojournalism, streeter, landscapes, studio, etc) in the hands of experienced photographers, always understanding that the picture itself will always reign supreme regardless of the camera and lens used, and previous extraordinary standard lenses like the Summilux-M 50 mm f/1.4 ASPH are able to give such a tremendous image quality that even the most experienced professional photographers won´t be able to draw its full potential in real photographic situations, something that also happens with the Apo-Summicron-M 50 mm f/2 ASPH.
But it isn´t less true that the most amazing feature of the Apo-Summicron-M 50 mm f/2 ASPH lens is not only the unchallenged reference class image quality it is able to currently deliver, but very specially that irrespective of the image quality that the photographer is able to attain with it (whether shooting handheld, on a tripod, etc), for the first time in history the image quality rendered will be practically the same in center, borders and corners, what is an unprecedented feat in the optical domain:
´ This is a benchmark that we´ve set, one that will remain in place for years to come. It is a continuation of optical development as we know it at Leica, building on the fast lenses which we have designed in recent years, and so having produced a standard lens in the high performance category of a type that has never existed before ´. Peter Karbe
Finally, in my opinion, though this lens has been created to synergize to the utmost possible with the excellent black and white sensor of the Leica M Monochrom, the certainly spectacular 15 x 20 inch colour enlargements made on photographic paper from DNG archives generated by a Leica M9 connected to an Apo-Summicron-M 50 mm f/2 ASPH which I have had the chance to see, make me have the firm conviction that the results can be truly astounding - maybe approaching the ones rendered by the Leica M Monochrom, but in colour - in future Leica M cameras featuring more advanced sensors with better performance at high ISOS, since I do believe that the unmatched image quality delivered by this lens with which Leica has made history once again, gathers the best of the best of two lines of thinking regarding the look of images:
a) The trend of Japanese lenses for 35 mm format cameras, started by Nikon with its legendary Nippon Kogaku rangefinders and its lenses during late forties and decade of fifties, followed by the lenses of the Nikon F System and other brands from 1959, with clear stress on the global sharpness of the main contours of the subject along with their textures and bright colours, trying to give images an immediate visual impact.
b) The Leica philosophy, that gives great importance not only to the contrast, but also to the subtlety of colours and the tonal gradation of gray scale.
If we add to it that Leica has been able to attain all the aforementioned qualities of the Apo-Summicron-M 50 mm f/2 ASPH with an astonishing miniaturization of dimensions and weight (Larger Diameter: 53 mm, Length: 47 mm and Weight: 300 g) which has been about to equal the compacity of the Summicron-M 50 mm f/2 (Larger Diameter: 53 mm, Length: 43.5 mm, Weight: 240 g), it seems clear that Max Berek,
pioneer in the design and manufacturing of Leitz lenses for 35 mm format Leica cameras almost a hundred years ago, would be very proud of the Apo-Summicron-M 50 mm f/2 ASPH, with which once more the firm which was born in Wetzlar (Germany) has surpassed itself once again.
Copyright Text and Photos: José Manuel Serrano Esparza. LHSA
