This is a followup from the post "The Perfect Lens" from last Tuesday. In that post, I wrote the following about Harold Merklinger:
"I once asked Harold Merklinger what his favorite lens was. Harold, an e-friend-I've-never-met, was Chief Scientist of the Canadian Defence Research Establishment Atlantic and retired as that agency's Director-General. He wrote "A Technical View of Bokeh" as part of the trio of articles that introduced that concept in this hemisphere. He's an enthusiastic polymath of technical photography and has written several books on optics. His answer was that he liked the older 55mm-filter-thread version of the Leica Summilux-R. When I asked him why, he said, 'Oh, I suppose it just does everything I want a lens to do.' Which seems a very casual answer until you consider the weight of technical expertise backing the statement up."
Here's the current story about that....
Written by Harold M. Merklinger
OK Mike, let me update my comments!
I still have the old Leica Summilux-R 50mm ƒ/1.4* [E55 —Ed.].
First thing I did was to look for a test of the Leica 50mm ƒ/1.4 Summilux-R that I believe I did using a Canon 5D with Leica R adapter six or seven years ago. The only result I could find was at ƒ/1.4. But it was easy enough to repeat the test today using an EOS 5DS R. The lens has only a very slight hint of chromatic aberration—which accords with why I would have liked it. Back in the "film era" it was essentially impossible to deal with things like chromatic aberration and distortion, so these were important to get rid of through choice of lens. The lens is also excellent in the centre at all apertures. At the edges, there is a sharp image which which looks to be superimposed on a much softer image. The softer image disappears as one stops down until it is essentially gone by ƒ/8.
There is a later version of the 50mm ƒ/1.4 Summilux-R [E60] which is reputed to be much improved, but I never had or tested that version.
The other lens you pictured—the Leica M 50mm ƒ/1.4 Summilux-M ASPH—I have one of those too, and I did test it on an M9 in 2010. It is a much better lens, but for critical use I still would not want to use it at apertures larger than ƒ/4.
That is typical of what I find with many lenses: for demanding purposes they need to be stopped down to ƒ/4. There are exceptions of course. The Leica 90mm ƒ/2 Apo-Summicron would be one. It does just fine wide open. And there are several others I could name, but few of them have focal lengths shorter than 90mm.
For more than a decade I have been wondering why manufacturers don't just give us small, lightweight, ƒ/4 lenses. It may have started to happen. One of my favourite lenses today is the Leica 24mm ƒ/3.8 ASPH in M mount. It is eminently usable wide open, and nigh perfect just half a stop down. The related 21mm ƒ/3.4 Super-Elmar-M ASPH is even better, but wider than I use frequently. We need more lenses like those two.
The lens I use most today will perhaps surprise many. Especially those who have not tried it. It is the Canon 24–70mm ƒ/4L IS. I included this on the EOS 5DS R when I tested the Leica 50mm ƒ/1.4 Summilux-R earlier today. At 50mm and ƒ/4 it was clearly better than the older Leica lens, with even less chromatic aberration and only a very slight softness at the edges and extreme corners. At ƒ/5.6 it is everything I could ask for today. And it is similarly good at other focal lengths, although it does show some chromatic aberration and distortion—easily eliminated "in post" today. This lens—new—cost me $400 Canadian (US$300) on sale! Now it could be that I got a "good one"—I have only tested the one I purchased.
Another excellent lens by any standard is the similarly low-priced Canon 40mm ƒ/2.8 STM. Good to the corners, even wide open.
*The lens nearly met its demise a few years ago when I was testing it on the 5D. The clutch that fastens the focusing ring to the focusing helicoid was loose, unbeknownst to me. Focusing closer tightened the clutch and moved the lens outwards. Attempting to focus farther away loosened the clutch enough that the optical unit did not in fact move. As I struggled to find focus, the optical unit fell right out of the helicoid! Fortunately, I was able to catch it before it reached the concrete step I was standing upon!
©2016 by Harold M. Merklinger, all rights reserved
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Featured Comments from:
Barry Reid: "Now the comment about the Canon 24–70mm ƒ/4 makes me very happy. I have in my own unscientific and just-from-use sort of way come to the conclusion that this is the best zoom I have ever used. Mine replaced a Sony FE 24–70mm ƒ/4, mainly because I was unhappy with the Sony's handling. Once I got it into use I couldn't believe how good the files were. It's also worth noting that while it does have some distortion, it is class-leading at the wide end which is part of what drove me to buy it over the other Canon and Tamron offerings as I just don't believe digital correction can be penalty free."
Hugh Crawford (partial comment): "Something nobody seems to remember about the lenses of the SLR era is that hardly anyone bought fast lenses to shoot wide open. We bought fast lenses so that we could focus them. In the manual focus era you needed a fast lens so that split image and microprism focusing aids wouldn't go dark, and because the ground glass screens in manual focus cameras are much darker than the screens in autofocus cameras. Also, focusing wide open and shooting stopped down a couple stops let depth-of-field take care of focusing errors and focus shift. Then of course pro level autofocus SLRs were optimized for fast lenses to increase focusing accuracy because a larger aperture effectively increased the baseline of the phase detection system.
"And of course even the most crummy fast lenses looked better than good slow lenses standing in the store looking through the camera. Just like cheap loudspeakers."