essbe
Newbie
Hi! I've been wondering about this issue for quite some time, as I use both Leica cameras and FSU-cameras. I know the theory of difference in focal length, but I wanted to test what effect this had in practice, and if it is relevant at all. The findings were quite interesting to me, and as this question seems to arise from time to time, maybe it could be interesting to someone else. I do not know if this should belong to the Leica or FSU-forum. Maybe it is of most interest to people using digital rangefinders, then this thread could be moved.
The test is on youtube, if you are interested in watching long and slow tests you can look for soviet lenses on leica cameras, and find that or something else like it. In other cases my findings are presented in post #8 below.
The test is on youtube, if you are interested in watching long and slow tests you can look for soviet lenses on leica cameras, and find that or something else like it. In other cases my findings are presented in post #8 below.
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Chriscrawfordphoto
Real Men Shoot Film.
Soviet lenses don't focus accurately on Leicas no matter how much some people wish they did. I've shot with a number ofthem and NONE focused accurately. They were not designed to.
essbe
Newbie
Yes, I know the theory behind it. I go through it in the video. I haven't tested hundreds of them, but most of the ones I have seem to focus ok though, while some are more problematic.
I have used hundreds of them, and own a lot of them. The focal length on the Jupiter-3 is given as 52.4mm +/- 1%. Go through enough of them, keep the ones that are on the short end of the focal length- and focus is accurate across the whole range. The others- Shim them so focus agrees at 8ft~10ft or so, often depends on the exact focal length. Set the focus so that close-up/wide-open is within the DOF, about 1/3rd into it- not 1/2. Stop down between F2 and F2.8, depending on the exact focal length, for infinity. The J-3 is over-corrected for spherical aberration- means focus shifts towards infinity. AT worst: move the rear group closer to the front group to reduce the focal length. I lost track of how many J-3's I currently have. Some 20 or so. I've also used ~70 CZJ 5cm F1.5 Sonnars, converted more than 50 to Leica mount- the same holds true. This is the lens that the J-3 is based on. I have 9 CZJ 5cm F1.5 Sonnars in Leica mount, cherry-picked. The worst- needs F2 for infinity.
The latest 1952 Jupiter-3 5cm F1.5, shimmed this past July (2022) for my Leica. It's one of the best I've ever seen, Zeiss Optics.
Close-up, Infinity, and real-use. All wide-open.
The latest 1952 Jupiter-3 5cm F1.5, shimmed this past July (2022) for my Leica. It's one of the best I've ever seen, Zeiss Optics.
Close-up, Infinity, and real-use. All wide-open.
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You must also remember that the shape of the FSU Cam follower is a wedge, not a wheel. There are many lenses that work on a Leica that will jam on an FSU camera. Summarit 5cm F1.5: jams. Nikkor 5cm F2 in LTM- works.
In the end- best to use FSU cameras with FSU lenses. I calibrated the RF of my Zorki 3M to work with the Nikkor 5cm F2 "just because".
The lenses made for the Leica will front focus on the FSU cameras, and the shim needs to be reduced. I adjusted the camera instead.
In the end- best to use FSU cameras with FSU lenses. I calibrated the RF of my Zorki 3M to work with the Nikkor 5cm F2 "just because".
The lenses made for the Leica will front focus on the FSU cameras, and the shim needs to be reduced. I adjusted the camera instead.
This J-3 was more typical of one with a longer focal length. Was an early one that I worked on. These days: I would change the spacing of the groups.
Distance at F1.5 (falls short) and F4.
Distance at F1.5 (falls short) and F4.
essbe
Newbie
Hi Brian, and thank you for all of your posts about this. Good to know about the Summilux! I have owned a few jupiters, but have just been using them on soviet rangefinders and mirrorless cameras, because of this focus incompatibility issue. What I found when I tested was that my Zorki-5, which I mostly use, focused basically the same on my Leica M2 and my Leica iif, with all lenses. The only ones I am a bit hesitant about are the Jupiter-8 and Jupiter-3. When I checked they are also tighter in field of view compared to my Industars-22, -50 and -61 (I do not have hundreds however, more like 2 or 3 of each). The Industar-61 has the exact same field of view as my Leitz Elmar. Unfortunately I do not have any Zorki-3s or -4s anymore to check, but I am wondering if it could be that the Jupiters have a bit longer focal lengths than the rest, and that this focus incompatibility mainly concerns jupiter lenses, and the cameras made with the Jupiter-8 as standard lens (Zorki-3, -4, Drug and Leningrad)? Or maybe I just have a too small sample size. Have you seen any difference of that kind? I like the Jupiter-8, but as I mostly shoot at f8, I have started to use tessars more instead.
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I've seen documentation that the I-22, I-26m, I-50, and I-61L/D are all built to the same 52.4mm "nominal standard" as the Jupiters.
These lenses are all over-corrected for spherical aberration, as is the Elmar 5cm. The focal length of the center of the lens is longer than the focal length of the edges. The focus shift of the Elmar 5cm F2.8 is a WHOPPING 0.11mm. Focus shift on Tessar formula lenses in general tends to be fairly substantial- but not all the same. The DOF covers the area, but- it is Possible that the magnification of the image is changing enough across the F-Stops to produce what you are seeing.
Another item I'll have to add to the "to do list". I picked up a Nikon Z5 recently, will be easier to measure with it than the Leica.
These lenses are all over-corrected for spherical aberration, as is the Elmar 5cm. The focal length of the center of the lens is longer than the focal length of the edges. The focus shift of the Elmar 5cm F2.8 is a WHOPPING 0.11mm. Focus shift on Tessar formula lenses in general tends to be fairly substantial- but not all the same. The DOF covers the area, but- it is Possible that the magnification of the image is changing enough across the F-Stops to produce what you are seeing.
Another item I'll have to add to the "to do list". I picked up a Nikon Z5 recently, will be easier to measure with it than the Leica.
maizenberg-cameras : Isaak S. Maizenberg : Free Download, Borrow, and Streaming : Internet Archive
All You Need to Know about the Design and Repair of Russian Cameras
archive.org
A definitive reference that gives both the J-8 and I-22 the same focal length of 52.4mm.
PDF download available! I just downloaded it, incredible reference.
The Author states that a camera must be adjusted when upgrading from the Industar-10 to a newer lens. The I-10 was the original Soviet lens, and most likely an Elmar copy. The I-22 and subsequent lenses are post-war and based on Zeiss lenses. Those are made to the 52.4mm spec.
Welcome to RFF. I like discussing Optics. Also made me look again for Maizenburg! Found It this time!
essbe
Newbie
Yes, I have a passport for the Industar-61 that says 52.4mm, but when I check field of view it is exactly as the Elmar, and clearly wider than the jupiters. The I-22 and I-50 are also wider than the jupiters, but a little more narrow than the industar-61 and the elmar. I found that the distance scale on both collapsible i-22 and i-50 are off too, so I don't really trust written numbers concerning these lenses. AS for focus shift, yes, I found out that the elmar focus shifts alot too, and a Jupiter-8 set to focus on f4 probably shifts less at f8 than the elmar. If Zeiss had released a 50mm f4 sonnar back in the day alot more photos throughout history would have been in focus...The industar-50 seems to shift very little, but there is some at f8. The other ones have significant shift, atleast on digital. It seems to me as if focus shift is a bigger problem than compatibility issues regarding these lenses and cameras, but less talked about maybe. And things like physical incompatibilities of course.
essbe
Newbie
The industar-61 also shfts, unfortunately, but it is a curious lens. Actually sharper in the corners than in the center, and the corners do not focus shift. But that is perhaps the common thing?
Probably after I retire...
Spherical Aberration, the cause of focus shift, is "by design". Without it, the DOF of a fast lens would be so narrow that nothing would be in focus. Stopping the lens down, used with a Rangefinder or an SLR using wide-open focusing needs to be compensated. The photographer can do this by knowing the lens and focusing past what the camera indicates.
OR the mechanical engineer could have linked the Aperture mechanism to the Barrel and moved the optics as you stop down. One day- I'm going to Hack one of my Parts J-3's to do that. Fix the Aperture ring in the Mount and move the barrel to set the F-Stop. The movement of the barrel in the threaded aperture ring will compensate for focus shift. This would not have been very complex to implement. Easier than a Zoom lens.
My earliest Sonnar 5cm F1.5, from 1932- the test batch, was optimized for F2.8 or so. Sonnars after that- all mine were optimized for F1.5.
Spherical Aberration, the cause of focus shift, is "by design". Without it, the DOF of a fast lens would be so narrow that nothing would be in focus. Stopping the lens down, used with a Rangefinder or an SLR using wide-open focusing needs to be compensated. The photographer can do this by knowing the lens and focusing past what the camera indicates.
OR the mechanical engineer could have linked the Aperture mechanism to the Barrel and moved the optics as you stop down. One day- I'm going to Hack one of my Parts J-3's to do that. Fix the Aperture ring in the Mount and move the barrel to set the F-Stop. The movement of the barrel in the threaded aperture ring will compensate for focus shift. This would not have been very complex to implement. Easier than a Zoom lens.
My earliest Sonnar 5cm F1.5, from 1932- the test batch, was optimized for F2.8 or so. Sonnars after that- all mine were optimized for F1.5.
I do not have a similar diagram for the Tessar, but the edges are probably similar to what happens in the Sonnar. The result at the corners- makes it look like the DOF is not even across the image.
KoNickon
Nick Merritt
Interesting stuff, guys, though way over my head. For M39, FSU with FSU = just follow that rule, I think.
p.giannakis
Pan Giannakis
My Jupiter-9 backfocuses on my Leica IIc. At f/2 it focuses behind the subject (notice the tree trunk behind)
It does seem to focus accurately at f/2.8 though.
It does seem to focus accurately at f/2.8 though.
Conservation of Inconvenience at work here, and a couple of simple equations.
At one time- the Jupiter-3 was a fraction of the cost of a Nikkor 5cm F1.4, Canon 50/1.5, and Carl Zeiss Jena 5cm F1.5 Sonnar in LTM. Get a good one, calibrate it properly- and you had a great super-speed Sonnar for your Leica camera. These days- the best ones are gone, the remaining ones go for many times what they used to. Not the bargain they used to be.
The Jupiter-9 is just too far off for the LTM version to focus correctly on a Leica. The focal length would have to be reduced to 83.2mm from 84.5mm to work properly with the RF. The later Black versions have a shim for the rear triplet, removing it helps. My solution is to use a Contax/Kiev J-9 with an adapter, which works across the full range. My best LTM J-9: I polished down the LTM-M adapter and then shimmed the lens.
THESE: Jupiter-9 in LTM, using an LTM to M-Mount adapter that I ground down to ~0.8mm or so. Real trial and error.
It "works better" because the error of using the 0.8mm thick adapter partially cancels the error due to the lens not being calibrated to the Leica standard.
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These are with the 1955 KMZ J-9 in Contax/Kiev mount, using the cheap Chinese adapter that is no longer made.
All wide-open.
All wide-open.
essbe
Newbie
Wow, interesting stuff. A lens free of focus shift, as you describe, would be wonderful, if that would ever happen. Concerning the jupiters and industars (interesting about the industar-10, didn't know that), since my industars-50 (tested 2 of them) and -61 (especially this one) are closer to the leitz elmar than the jupiters, both at 2m and at infinity, does this indicate a similar focal length to the elmar, or is it just an effect of distortion, as the industars are more distorted than the elmar (or can it be said that similar focal length = similar field of view)?
Attachments
essbe
Newbie
All of these images shot at f8, I think, not the f-stops written in the images