Liking the Leica SL with M and TL lenses

Earlier this year I bailed out of the Leica SL system purely on the basis of weight and bulk. For me, no longer a youngster, the combined weight of the SL and the superb 24-90mm Vario-Elmarit zoom was just too much to handle. And the other SL lenses, particularly the new 50mm Summilux, are just as much a handful. But, despite selling the zoom (the only native SL lens I possessed) I have not lost my love of the camera itself.

When used with M lenses or auto-focus optics from the TL line-up, the SL is a completely different animal. Sure, the body tips the scales at 850g, nearly 200g heavier than the M10. But when you bear in mind the superb built-in viewfinder and the huge and comfortable grip, the difference is no longer so significant. 

Since I sold the portly Vario-Elmarit I’ve been restricted to non-SL lenses and I am definitely warming to experimenting with both M and TL. The SL is particularly good with those M lenses that are sometimes difficult to focus wide open, lenses such as the 50mm Summilux and, particularly, the fussy Noctilux.

Now the 50mm f/0.95 Noctilux-M ASPH isn’t an everyday lens unless your name happens to be Thorsten von Overgaard. But it is one of those optics that, despite its weight, is simply wonderful and one that most Leica enthusiasts dream of having in their bag. It’s a special occasion lens but one that seldom fails to captivate. In some ways it has more allure than the clinically sharp but slower 50mm Apo Summicron.

Noctilust

The Noctilux and the SL constitute a marriage made in heaven. I wrote words to that effect last year. It is big enough and fat enough to resemble a small native SL lens without protruding like a tiny beak as do most M lenses when mounted on the big mirrorless.

And when it comes to focus, the Noctilux has definitely met its match with the SL. This optic, wide open, is notoriously difficult to focus on a rangefinder, especially for many older users whose eyesight is less than perfect. With such a narrow depth of field, achieving the precise focus point and judging how much of the scene will be sharp is a challenge, even on on the latest M10 with its bigger finder window. The Visoflex helps the M10 focus, of course, but it is the massive 4.4MP viewfinder of the SL that really tames the Noctilux. The amount of detail is such that focus is relatively easy, although you still have to be aware of the problem of ultra-narrow depth of field. And a further bonus that can’t be ignored is that the electronic shutter of the SL permits full-aperture shooting even in bright conditions. With the M you need an ND filter to achieve that party trick.

Since the Spring, though, I’ve had another set of lenses to use with the SL. Unlike the M lenses, which require an adapter, the autofocus zooms and primes made for the TL system use the same native mount. They are tiny and very light in comparison with SL lenses and they do offer surprisingly slick autofocus. I bought them in anticipation of the TL2 which, at the time, I thought would have a built-in viewfinder. Now I’m on hold in the APS-C stakes, so I am using the opportunity to give these lenses a thorough workout on the full-frame SL.

Pixel squeeze

There is a snag with the TL lenses, however. Unlike as is the case when mounting full-frame M lenses on the APS-C TL — where the camera is using the central part of the lens but covering the full sensor — the reverse is true when crop lenses are mounted on a full-frame camera such as the SL. Only the centre of the sensor is addressed, resulting in a smaller image, equivalent to the size of an APS-C sensor. The on-paper loss looks a bit frightening, although it is in line with the 1.5 crop factor. Whereas both the TL2 and SL produce full-size images of 6000 x 4000 pixels (24MP), a TL lens mounted on the SL results in an image of 3936 x 2624 pixels or just 10.33MP. 

The interesting question is just how significant that shortfall is in real-world photography. On paper it looks pretty drastic, as I said, but all is never exactly as it seems. For instance, the pixels of the SL are bigger than those of the APS-C sensor in the TL2 and this could well bring benefits in low-light performance and in extending dynamic range.

Interestingly, for instance, the Sony A7S, renowned for its high ISO performance and dynamic range, manages with a miserly 12MP sensor. Indeed, that is the whole basis of the performance of this camera. But 12MP on a full-frame sensor means biggie pixels, much bigger than those of the 24MP SL sensor.

Now I’m not suggesting for one minute that a 10.3MP crop of a full-frame 24MP sensor is going to rival the results from, say, the same lens on the TL2 with the full 24 million smaller pixels at its disposal. Logic dictates that this cannot be the case. All I am saying is that the bare figures do not necessarily tell the whole story and, when push comes to shove, the TL lenses are capable of good performance on the SL.

Be this as it may (and I have by no means reached any conclusion), I’ve read some encouraging reports of the use of TL lenses on the SL.

Is there any sense in having a full-frame camera and using crop lenses that reduce the image size so much? This is one of the aspects I shall be considering over the next few months. It’s an interesting question for anyone owning the SL and not wanting to cope with the weight and size of the native autofocus lenses. Buying the SL to use with existing TL and M lenses might just make sense. I aim to find out. 

It’s also interesting for those who are attracted by the TL2 but cannot accept a camera without an integral viewfinder. The SL is an alternative, if a rather costly and heavier alternative, to the lightweight TL. However, I don’t think anyone would suggest buying TL lenses just for use with the SL. If you have them, use them, but accept the limitations.

For M lenses on the SL, however, there are no compromises on pixel density or cropping. The M lenses retain their focal length on the SL whereas the popular focal lengths of 28, 35 and 50mm tend to be on the long side when mounted on APS-C. This isn’t the case, incidentally, with TL lenses mounted on the SL — they retain the same full-frame-equivalent focal length as on the TL. A 23mm TL lens behaves as a 35mm whether attached to the TL or SL. it can get confusing.

Secondly, you are using a native full-frame optic which is ultimately the best option. With M lenses you are enjoying a much smaller overall package — compare the 50mm Summilux-SL with the 50mm Summilux-M, for instance. They are chalk and cheese in size and weight but surprisingly similar in performance No, all you are really losing is automatic focus.

As I said, however, there are compromises with the TL lenses. I did a preliminary review of the SL with a TL lens, the 35mm Summilux, shortly after the SL was announced. Looking back on this article I see good results from the combination and I have great hopes for the rest of the TL bunch of lenses.

As I write this article I read that Steve Huff has also just reacquainted himself with the SL and asks whether it is still a good choice after two years. He thinks it is:

“Over the last two years I bought and sold a couple SLs and have had one back for a while now, and I have learned my lesson (I think). I will only sell this SL if Leica upgrades it, and even then, the new one would have to be substantially better for me to want to upgrade. This SL stays with me…..”

What can I say? I suspect I have a similar relationship with the SL. I am certainly looking forward to experimenting with various lenses, full and crop frame, and will bring you the results over the next few months. Got to find something to write about every day.

What are your experiences of using either M or TL lenses on the mighty SL?

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