Two points about the Leica SL, including the 50/1.4, and some curious musings

<p>It seems that the shipping date for the 50mm Summilux-SL is January next year:</p>

<p>http://leicarumors.com/2016/11/14/new-leica-sl-firmware-update-and-the-summilux-sl-50mm-f1-4-asph-lens-to-be-released-in-early-2017.aspx/</p>

<p>Note the criticisms that this lens is already getting for its size. I think people look at this a bit one-dimensionally, as if your only choice of lenses for the SL are the native ones. Some might wonder why you would buy a mirrorless system if you're also buying such big lenses. The answer is obvious: more accurate, more direct, more flexible (SLRs do not see exactly what the lens sees, contrary to popular belief). And this lens is probably going to at least match the Zeiss Otus, if not surpass it in almost every way.</p>

<p>But there's something interesting going on here. The filter diameter of the 50/1.4 is 82mm. Let's compare that with the 75mm Summarit-S, which has a filter diameter of 82mm. Hmm. That's interesting.<br>

<br />If you added a 1.4x teleconverter to the 50/1.4, it would become, approximately, a 70/2. That's 2/3 of a stop wider than f/2.5, and of course the filter diameter did not need to increase in width. That means that you can make a 50/1.4 that covers a 45x30mm sensor with a filter diameter of 82mm. It would be large, but that's the point I'm making.</p>

<p>I'm going to make a pretty big call here: the SL lenses, or at least some of them, can cover the image sensor of the S series. That's why they're so large. Which means, at least on paper, that the next S can be a mirrorless body, and will combine the 45x30mm sensor with the L mount.</p>

<p>A minor observation: the SL is not supposed to be a general purpose system. The M certainly is, however. It offers high performance while remaining compact, especially when you add the lenses. You can make a hybrid M-based system even more compact by using M lenses and a third-party mirrorless body.</p>

<p>Lenses designed to cover a full frame (24x36 mm) aren't necessarily large, as witnessed by generations of lenses for the M series cameras. However these lenses don't perform as well as they might if designed for a digital sensor, due largely to the high angle of incidence when the rear element is close to the image plane. Furthermore, with a digital camera, any faults in the lens are more easily seen than when used with film.</p>

<p>One solution seems to be designing a longer back focus distance, which reduces the angle of incidence at the sensor. Since the sensor is protected with a cover glass and filters, the lens should take that into account as an additional, if external, element. These features increase the size of the lens.</p>

<p>If the designers are thinking ahead to cameras with ever higher resolution, every effort is made to achieve the highest performance, usually requiring additional elements, which increases the size and weight. We've come a long way from 7 element Summicrons. Very high performance can sometimes be achieved with fewer elements with exotic glass and aspherical surfaces. The designer has choices depending on the intended use.</p>

<p>Are SL lenses designed to cover medium format? Unlikely. However you can make a quick check by observing the image circle of an unmounted lens. Lenses for a Nikon SLR are much larger than traditional Leica RF lenses. Would you assume they're designed for MF? Actually, excessive coverage can contribute to loss of contrast, due to light reflected in the camera.</p>

<p><em>"Two points about the Leica SL, including the 50/1.4, and some curious musings"</em><br>

<em><br /></em>a 50mm 1.4 lens at <strong>$5,300</strong><br>

I can wait till next year</p>

<p> </p>

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<p>the SL is not supposed to be a general purpose system</p>

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<p>Says who? So what <em>is</em> it for?</p>

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<p>That means that you can make a 50/1.4 that covers a 45x30mm sensor with a filter diameter of 82mm.</p>

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<p>Can't follow on how you arrive at that conclusion. The 45mm f/2.8 S lens already has 82mm filter thread; it's highly unlikely that a 50/1.4 for the S system could make do with it.</p>

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<p>the SL is not supposed to be a general purpose system. The M certainly is, however.</p>

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<p>Matter of opinion, I guess. I would consider the SL more of a general purpose system than any M (which becomes unwieldy to use as soon as one gets outside the 28-135mm focal length range that the viewfinder covers (and which is in reality only usable from 35-75)). The SL with its three lenses would make a nice travel kit (in terms of focal length coverage) but unfortunately, the lenses are rather large and heavy (and at least I would not be very comfortable hauling some $25K of equipment around).</p>

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<p>So what <em>is</em> it for?</p>

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<p>Beats me. It was announced as an alternative to the D5/1DXII for the professional photographer. A claim at least I put to rest when I tried it in the store, AF failed to perform under lighting conditions that wouldn't have had a D5/1DXII hesitate at all. And what good are 11fps if the viewfinder can't keep up?</p>

<p>Agree with you Dieter absolutely. I have no idea how Karim reached these conclusions. I thought the VF on the SL was wonderful as was the general feel of the camera. Size and value proposition was not so good. I think Leica consider it a professional system, which many people assume mean it is for the same people who would buy a 1DX or D5, but it is really aimed at the D810/5DIV people in my opinion.</p>

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<p>is really aimed at the D810/5DIV people in my opinion</p>

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<p>And/or 5DS/5DSR - and in that company, the 24MP sensor of the SL falls a bit short. I thought that the viewfinder was fine too - compared to what I've seen in EVFs from Sony. Still prefer very much the optical viewfinder in a DSLR (except for manual focusing).</p>

<p>The Leica SL has a 24 MP sensor today, but tomorrow it could be 50 MP or more. Those sensors are already available in FF size.</p>

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<p>tomorrow it could be 50 MP</p>

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<p>The one I can buy today doesn't have 50 though. And I doubt that the one I can buy today will magically double their MP count anytime. Coulda, shoulda, woulda - but doesn't. Equally, the M cameras could have a zooming viewfinder for decades, but still don't.</p>

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<p>I can buy today will magically double their MP count anytime.</p>

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<p>Say that again ;)</p>

<p>Do you think it is remotely possible that Leica would build a lens that beats the minimum requirements, like Sony does the G-Master lenses?</p>

<p>Edward, thanks for the pushback. :-)</p>

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<p>Lenses for a Nikon SLR are much larger than traditional Leica RF lenses. Would you assume they're designed for MF?</p>

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<p>SLR lenses have automatic aperture mechanisms. They can't be as small as RF lenses. If they can, I haven't seen examples of those.</p>

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<p>Actually, excessive coverage can contribute to loss of contrast, due to light reflected in the camera.</p>

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<p>The Zeiss Otus almost covers medium format. I have not heard of any complaints about excess coverage. Even 135 format lenses have excess coverage a lot of the time.</p>

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<p>The 45mm f/2.8 S lens already has 82mm filter thread; it's highly unlikely that a 50/1.4 for the S system could make do with it.</p>

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<p>The 30/2.8, 35/2.5, 45/2.8, 70/2.5 and 100/2 all have an E82 filter thread. I have already demonstrated that a 50/1.4, which has an 82mm filter thread, has larger aperture diameter than a 70/2.5 (35.7mm vs 28mm).<br>

<br>

The M is most certainly a general purpose system. It's the DSLRs which are niche products, as they excel at only one thing: AF speed and consistency (though some are criticized for poor performance). Even that unique selling point is now vanquished, although the M is not the challenger.<br>

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I concur with Robin who said that "it is really aimed at the D810/5DIV people in my opinion." I think even Leica agrees with that.<br>

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<p> the 24MP sensor of the SL falls a bit short</p>

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<p>I disagree. I have looked at DPReview's lab tests and the Q (same sensor) is sharper than the D800E. Why? Probably because Leica's cover glass is better. Photosite count is not the full story. ;-)<br>

<br>

So, as Edward suggested, we have to ask a reviewer to measure the image circle of the 50/1.4 SL. We'll see...</p>

<p> </p>

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<p>The M is most certainly a general purpose system. It's the DSLRs which are niche products</p>

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<p>Well, quite a ridiculous claim, so let's just agree to disagree. Rather pointless to argue that a camera type that has been relegated to backseat status for decades is more purposeful than one that has outsold it by a huge margin for decades.</p>

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<p>I have already demonstrated that a 50/1.4, which has an 82mm filter thread, has larger aperture diameter than a 70/2.5 (35.7mm vs 28mm).</p>

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<p>Ah, so that was the reasoning. Sorry, I don't see how the aperture diameter is relevant in determining either the front filter dimensions (aside from the fact that it can't be smaller) or the image circle size. The 55mm Otus uses a 77mm filter, the Nikon 58/1.4 a 72mm, the Nokton 58/1.4 makes do with 52mm, and the Nikon 1.4G uses a 58 (same size as the 1.8G).</p>

<p>There are indeed examples of lenses (Tamron 60/2, Nikon DX 35/1.8) that almost cover the larger FX format - but image quality in those "excess" areas is generally poor.</p>

<p>Most of the size and weight of SLR lenses comes from the need to increase the back focus distance. The lens elements alone are bout 25% larger in diameter on this account in a 50 mm lens. The disparity is inversely proportional to the focal length.</p>

<p>To some extent this carries over in lenses designed for mirrorless cameras. Increasing the back focus distance improves the telecentricity, reducing the angle of incidence. Compensating for the thickness of the cover glass on the sensor is important, but has little effect on the size and weight of the lens.</p>

<p>Otus lenses are large and heavy because they attempt to reduce aberrations as much as possible, often by adding many elements. The front element is larger, in part, because it is further from the actual diaphragm. We see this trend for premium lenses for mirrorless cameras too. Modern multi-layer coatings make this possible by reducing reflections and maximizing transmission. In the day, six element Summicron lenses (and Planar) were seen as an "improvement" over previous 7 element versions because the macro contrast was better. </p>

<p>The actual or apparent diameter of the diaphragm has nothing to do with the coverage (image circle). Otherwise you would need an hand truck to carry most large format lenses.</p>

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<p>Note the criticisms that this lens is already getting for its size. ...</p>

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<p>How can anyone look at the size template between the SL + 50mm f/1.4 and the M9 + 50mm f/1.4 and not wonder 'what were those Leica lens designers thinking'?</p>

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<p>'what were those Leica lens designers thinking'</p>

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<p>Bigger is better?<br>

Size matters?</p>

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<p>Bigger is better?<br />Size matters?</p>

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<p>... Oscar must be rolling over at this.</p>

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<p>Rather pointless to argue that a camera type that has been relegated to backseat status for decades is more purposeful than one that has outsold it by a huge margin for decades.</p>

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<p> <br>

If you're talking about cost, then I agree with you.<br>

</p>

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<p>Sorry, I don't see how the aperture diameter is relevant in determining either the front filter dimensions (aside from the fact that it can't be smaller) or the image circle size.</p>

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<p>It isn't relevant per se. But in comparison, these measurements are telling. Let's go back to our standard lenses, the Summilux-SL and the Summarit-S. The Summilux is faster than the Summarit, even with a 1.4x TC, and yet it is physically almost the same width. So if the faster lens is no wider than the slower lens, and the slower lens definitely covers a large image circle, it's logical to suppose that the faster lens can also cover that image circle.<br>

</p>

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<p>'what were those Leica lens designers thinking'?</p>

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<p>Exactly. This thread proves that point. :-)</p>

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<p>Oscar must be rolling over at this</p>

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<p>I don't think so. A new system needs new paradigms. We'll always have the M, thankfully.</p>

<p> </p>

<p>There must be a lot of lens designers thinking along the same lines. Look, for example, at 50 mm lenses designed for a Nikon, from the relatively compact 50/1.4 to the Zeiss Otus 30/1.4. The latter is completely manual, yet measures over 4" in diameter compared to about 2-1/4" for the Nikkor. We see the same thing for Sony FE lenses, ranging from about 2-1/8" for the Loxia 50/2 to 4" for the Sony/Zeiss 50/1.4.</p>

<p>It's all about squeezing the ultimate performance into the package. That may be the end point for Sony and Nikon, but traditionally it is the starting point for Leica.</p>

<p>If you think it's too big, don't buy it. There are plenty of compact cameras to choose from. Ditto if you think it's too expensive, but spare us the sour grapes attitude.</p>

<p>I use a Leica MM Rangefinder and Leica S(006) for a lot of work. I also use a Sony A7R-II with A and FE mount lenses.</p>

<p>I had an opportunity to use a SL for awhile (a very accomplished photographer friend was provided one from Leica along with the two zoom lenses). He was not particularly impressed with the short zoom nor was I, but found the longer one to be quite excellent.</p>

<p>IMO, the SL is a hyper-built, almost DSLR sized camera. In fact, the size and weight surprised me. Also, after all the hype, my expectations of the EVF were not met ... but in all fairness, I'm used to a S camera with a big, bright OVF. </p>

<p>I think the notion of the M being a versatile platform comes from acessories now available due to use of a CMOS sensor allowing live view and an EVF. So, M lenses can be used for traditional rangefinder photography, while R lenses can be used for wider and longer lenses. I do not happen to agree with that adaptation, preferring to keep the M a rangefinder system, while using technology to shrink the M size.</p>

<p>What has been an interesting development for me is the Techart AF adapter for use of M lenses on a Sony camera. I use one on my A7R-II with select M lenses and couldn't be more pleased (so far). It is quick, accurate, and provides more diverse use of my M lens investment. The whole system is quite small, with much smaller sized, fast aperture optics than the native FE lenses that continue to increase in size and weight.</p>

<p>- Marc</p>