Lens Review: Leica 50mm APO-Summicron-M ASPH

When the first 50mm f/2 Summicron was introduced in 1953 it was in screw mount for the then current Leica IIIf RD DA (red dial, delayed action). This was a full year ahead of the first M, the M3. Since then both the M cameras and the Summicrons have of course become photographic icons.

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The first Summicron quickly established itself as the benchmark for 50mm lenses for the 36X24mm format and with regular redesigns over the years it maintained its preeminent position. That was until 2004 when the 50mm Summilux ASPH was introduced. This new state of the art lens, which exploited the latest glass types, an aspherical element and a ‘floating’ lens group, soon established itself as the new benchmark.

Not long after the Summilux ASPH was announced I was at Solms and asked Stefan Daniel whether we could now expect an improved Summicron perhaps using an aspherical element and floating group. The answer was simple: Such a project had been investigated but the current Summicron was already such an excellent lens that the cost of any significant improvements would raise its selling price to at least the same level as the Summilux ASPH.

At that time this was not acceptable by the marketing department, and in any case there were other R&D priorities. The project was deferred. Since then the M market has changed radically. Thanks to the digital developments, the M system has again become a best seller for Leica. At this point it was considered that there would be enough demand to justify the cost of developing a very special Summicron, the absolute best-possible 50mm lens, a demonstration of Leica’s state of the art capability in optical and mechanical design and production.

50mm APO-Summicron arrives

The result is the 50mm APO-Summicron–M ASPH. Unlike the spectacular 50mm 0.95 Noctilux that practically shouts for attention, the new Summicron is a very modest looking lens. There is no outward indication of its exceptional qualities. However, as with all truly outstanding lenses, one look at the images it produces and the achievement is apparent. There is an unmistakeable quality and clarity.

During a brief visit to Wetzlar, before lenses became available to the public, I was lucky enough to be allowed to borrow a pre-production version for a few hours. Although I was unable to shoot any serious tests or comparisons, the images that it produced were enough to convince me that this lens was truly special and one that I just had to have.

I had a long wait. As we all know it was in fact some nine months after its first announcement before the first production examples of the new lens trickled onto the market. There is no doubt that, in regular production, consistently achieving the exceptional levels of precision that this design demands was not easy. Some early examples had flare problems and, because these were random, production was stopped for a while until Leica were confident that the exact cause had been identified and corrected.

General

As the picture shows the APO-Summicron is compact, little different in size from the regular Summicron. It is however very slightly heavier. Handling is easy and comfortable. One difference is that Leica have fitted a focusing lever. Some people like this but on the whole, whilst I appreciate the handling convenience with shorter focal lengths, with lenses of 50mm and longer I prefer to use just the focusing ring. I would also have preferred a greater rotation from the closest focus (0.7m) to infinity. I believe that this can sometimes help greater focusing accuracy.

At infinity there is minimal cut-off in the finder from lens intrusion. At close distances, as the viewfinder frame moves downwards and to the right to compensate for parallax, the intrusion increases but is still not significant. The lens is beautifully built, focusing is smooth and all the clickstop detents are positive. Interestingly the lens hood operation is new; a simple twist extends it, quick and positive.

Performance

Overall this is exceptional. I shot comparisons with the regular Summicron and a Summilux ASPH on a variety of infinity and close-up subjects. At full aperture the APO is already outstanding. Stopped down to f/2.8 it performs as well or better than any of its sibling lenses do at f/5.6 and when itself stopped down to f/5.6 it remains ahead with exceptional edge-to-edge rendition of the finest detail. For reference I have reproduced here the official MTF curves for the 50mm Apo Summicron and the Summilux ASPH at full aperture and at f/5.6. Curves for f/2.8 and also those for the other 50mm lenses are all shown on the Leica website and are well worth a look.

A very high level of performance is maintained right into the close-up zone even at the nearest focused distance of 0.7m. The regular Summicron is a very good lens in the near range as is the Summilux ASPH but the APO-Summicron is superior to either of them, most noticeably at wider apertures and in terms of edge performance.

Overall the gains achieved by the apochromatic corrections are notably evident in the pure rendering of colours and the ability to distinguish subtle nuances of tone.

By f/5.6 vignetting is at the theoretical minimum for a 50mm lens. In any case it is well controlled by the camera firmware of digital M models. Distortion at 0.4% is minimal and of no consequence in practical use.

I shoot a lot against the light and have had no problems with flare or internal reflections in more than two years of regular use. A practical example can be seen in the canal picture to the left. This was taken in an extreme contre-jour situation with not only a very bright low sun just outside the picture area but also an exceptionally bright reflection coming off the water.

Conclusion

This is a stunning lens. Image quality is superb, true leading edge performance and likely to be the benchmark for some time yet. Over the past two years I’ve been using it first with an M9 and more recently with an M-P model 240. I am consistently wowed by the quality of the images that it produces. Nevertheless this is a very expensive lens indeed, second only to the f/0.95 Noctilux in the M line-up and it does take some real effort to justify its purchase.

However, as mentioned above, as soon as I looked at my images from that brief experience with the pre-production lens in Wetzlar there were no doubts. This was an exceptional lens and I convinced myself that I really must have one. Regretfully this meant selling several other lenses including an excellent 50mm Summilux ASPH to fund the purchase. Suffice to say that I have absolutely no regrets.

© Brian Bower FRPS 2015

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50mm APO-Summicron Gallery