insf Posted April 1, 2015 Share #1 Posted April 1, 2015 Advertisement (gone after registration) Hey there, I'm tearing my hair out at this point and would love to get some outside counsel. I'm using a latest-generation 50mm Summicron and am noticing some focus shift starting at f/4. The focus is tack-sharp at f/2 and f/2.8, but it seems like the lens begins to back-focus at f/4. I'm testing the lens at minimum focusing distance. After hearing about the long wait-times to get your camera/lens calibrated, I'm really hesitant to go this route. I initially sent the lens to DAG Camera Repair to fix a loose focus ring and mentioned the back-focusing issue. He said that the lens checked out for him. Strangely, I don't notice these focus issues with my 35mm or 90mm, so I'm completely perplexed as to whether this is a problem with the body or the lens. So here are my questions: Does this focus-shift issue normally affect the latest-gen 50mm Summicron? If the problem is with the lens, can it ever really be fixed or will the body just be adjusted to account for its misalignement? If I have the body calibrated for this lens, does this mean that the calibration woud be off for my other lenses? Are the wait-times for Leica repair as crazy as I have heard (e.g., 3 months or so)? Any help would be greatly appreciated, the sooner this is behind me, the better. Thanks! Link to post Share on other sites More sharing options...
Advertisement Posted April 1, 2015 Posted April 1, 2015 Hi insf, Take a look here M240 or Lens Calibration issue?. I'm sure you'll find what you were looking for!
FlashGordonPhotography Posted April 1, 2015 Share #2 Posted April 1, 2015 I can't speak for the Summicron but I can give general information on focus shift. Focus shift is a property of a lens not a camera body. Focus moves backward as the aperture is stopped down as the aperture diaphragm is a part of the optical path of the lens. If a lens design has focus shift it can not be "repaired". But you can have the lens calibrated so that it is perfect at a slightly stopped down aperture instead of wide open. This means it will slightly front focus wide open but hopefully DOF will mask the effect. I have a 35mm Summilux pre FLE calibrated to F2 and it works great for me in real world conditions. It's the lens that gets adjusted. Do NOT adjust a body to a lens with focus shift or all your other lenses will be off. Focus shift is usually most noticeable from a couple of stops from wide open until eventually it gets taken over by DOF around f8. Leica repair times is variable. The US seems to better than some other places. Link to post Share on other sites More sharing options...
jaapv Posted April 1, 2015 Share #3 Posted April 1, 2015 Nearly all shorter lenses focus shift to a lesser or greater degree. This cannot be cured by adjustment. the only thing you can do is optimize it at your favorite aperture and compensate or disregard. I recommend the latter. Normally you will only see this when viewing at 100% or more aka crazy magnification. It will not have any impact on your photographs though. If your lens is fine wide open, just start taking photographs. You’ll be pleasantly surprised. Link to post Share on other sites More sharing options...
Mornnb Posted April 1, 2015 Share #4 Posted April 1, 2015 If the lens focuses perfectly at f2 and does not at f4, then it's not the camera. It's the lens. Many 50mm lenses suffer from focus shift, and this is an issue that impacts DSLR autofocus and rangefinder systems due to focus systems that function independent to the lens aperture settings. Canon's EF 50mm 1.2 is notorious for it. As is the Zeiss 50mm Sonnar ZM. Double gauss lenses frequently have issues with focus shift and the Summicron is not immune to the laws of physics. Telephoto and retrofocal lens rarely suffer these issues. Hence why the Zeiss Otus and Sigma Art 50mm went for retrrofocal designs. Problem is you need a huge lens with many elements for such a design. Apparently even the 50mm APO Summicron has very slight focus shift, according to diglloyd. Link to post Share on other sites More sharing options...
thighslapper Posted April 1, 2015 Share #5 Posted April 1, 2015 I'm testing the lens at minimum focusing distance ....... errr ...... How often do you use an 50/2 at 0.7m ...? At normal distances you may find there is less of an issue. Also, you have live view so I would check things with a tripod and compare manual focussing with live view on the camera..... Link to post Share on other sites More sharing options...
insf Posted April 2, 2015 Author Share #6 Posted April 2, 2015 Thank you so much for the replies - they're tremendously helpful. I'm a little bummed about this, but it's definitely something I can live with. I've been practicing with adjusting the focus to compensate for focus shift and it hasn't been a huge effort. The reason why this became a big issue is that my wife and I just had our first child and I've been using the 50mm to photograph our new baby. I'm constantly focusing at the minimum focusing distance, so this issue reared its head. Thanks again so much for the help - it's been quite the educational experience. Link to post Share on other sites More sharing options...
wlaidlaw Posted April 3, 2015 Share #7 Posted April 3, 2015 Advertisement (gone after registration) I gave up with the 50 Summicron, which is a fairly elderly design, after having three different examples. It aperture shifts and can also suffer from flare. One example had what both I and my local lens man thought was a badly cut helicoid, as it was in focus at infinity but went progressively further out of focus as you got closer. For a mid speed 50mm lens, I use the 50mm ZM Planar, which has no noticeable aperture shift, has very high resolution/MTF's and is extremely flare resistant. The only downside is that it is quite a bit larger than the very compact Summicron but it is still a lot lighter than my 0.95 Noctilux. In effect Leica have recognised the age of the 50 Summicron lens and its replacement, albeit at a very high price, is the 50APO Summicron. One reviewer felt that the ZM Planar was pretty close in quality of output to the 50APO but at a very different price point. Wilson Link to post Share on other sites More sharing options...
Jeff S Posted April 3, 2015 Share #8 Posted April 3, 2015 Strangely, I don't notice these focus issues with my 35mm or 90mm The 35 Summicron ASPH has been known to focus shift; mine does at f4 and f5.6 (same as reported with Sean Reid's review sample). No worries, though, as it's easily compensated and not really a problem in my prints in any event. Fact of life with many wide-ish, fast-ish lenses. Jeff Link to post Share on other sites More sharing options...
bocaburger Posted April 3, 2015 Share #9 Posted April 3, 2015 Wow then I guess I'd better send my LTM collapsible Summicron and tabbed 11819 in for service, because neither of them has noticeable focus shift like they should. Link to post Share on other sites More sharing options...
CheshireCat Posted April 7, 2015 Share #10 Posted April 7, 2015 Or just use the EVF. The RF is sooo last century Link to post Share on other sites More sharing options...
Mornnb Posted April 7, 2015 Share #11 Posted April 7, 2015 But the VF-2 is so 5 years ago! Link to post Share on other sites More sharing options...
viramati Posted April 7, 2015 Share #12 Posted April 7, 2015 My lux 50 asph focus shifts slightly and it has been my most problematic Leica lens having been back to Germany 4 times now for various problems the most annoying of which is that it keeps going out of focus-patch calibration at infinity, this seems to happen after a while even if I haven't used the lens (and before people say it's the camera all my other lenses are perfect) Link to post Share on other sites More sharing options...
ahklein Posted April 8, 2015 Share #13 Posted April 8, 2015 I can't seem to take images at the decisive moment, as one would need with a child, using the EVF. There always seems to be a delay, even without advanced metering. Link to post Share on other sites More sharing options...
CheshireCat Posted April 8, 2015 Share #14 Posted April 8, 2015 I can't seem to take images at the decisive moment, as one would need with a child, using the EVF. There always seems to be a delay, even without advanced metering. Agreed. That is due to the M missing some critical "latest" (8 years old) technology features such as low-delay EVF preview and electronic first curtain (EFC). Link to post Share on other sites More sharing options...
Mornnb Posted April 9, 2015 Share #15 Posted April 9, 2015 New EVFs have faster frame rates but haven't fixed the problem. Even with the state of the art EVF there is plenty of lag. The Sony A7R has a quarter of a second shutter lag plus a long viewfinder black out time, especially if it shows you a preview of the image. EVF is not a good device for capturing a decisive moment, which is why you want it as an option on a camera rather than a replacement for the rangefinder. Link to post Share on other sites More sharing options...
thighslapper Posted April 9, 2015 Share #16 Posted April 9, 2015 ..... and a lot of this depends on implementation ...... on the Xvario .... which uses the same evf ..... half depressing the shutter after taking a shot gets rid of the preview and allows you to view the active image and take a new shot almost immediately and with hardly any lag ...... Link to post Share on other sites More sharing options...
viramati Posted April 9, 2015 Share #17 Posted April 9, 2015 New EVFs have faster frame rates but haven't fixed the problem. Even with the state of the art EVF there is plenty of lag. The Sony A7R has a quarter of a second shutter lag plus a long viewfinder black out time, especially if it shows you a preview of the image. EVF is not a good device for capturing a decisive moment, which is why you want it as an option on a camera rather than a replacement for the rangefinder. I am afraid that I have to disagree as the A7II and A7s both have electronic first shutter and no shutter lag when taking a shot and also there is no black out of the EVF after a shot is taken (unlike the M240 where yo can't see the image for about 1sec after taking a shot). the A7r doesn't have the option of the electronic first shuttle so it suffers from shutter lag as does the M240 with the EVF. Link to post Share on other sites More sharing options...
jaapv Posted April 9, 2015 Share #18 Posted April 9, 2015 There is a short blackout, but it is a frozen image. You can use the M240 the same way, albeit with a longer frozen image, but it is far less annoying than the viewfinder going black. Link to post Share on other sites More sharing options...
viramati Posted April 9, 2015 Share #19 Posted April 9, 2015 There is no blackout on either my A7II or A7s after taking a shot. There is the obvious blackout for the split second that you take the shot as the shutter curtain closes much the same as the mirror going up and down on a DSLR. There is definitely no frozen image on the Sony A7 series cameras unless you have preview turned on. This blackout time after taking a shot is the most annoying thing that I have with the M240 EVF, I can live with the resolution but that damn blackout time makes action work impossible. Link to post Share on other sites More sharing options...
FlashGordonPhotography Posted April 9, 2015 Share #20 Posted April 9, 2015 The image review in the viewfinder of the A7 series is able to be turned on and off at will. The camera has a 1/2 second image review set by default. I have it turned off in my Sony cameras and I get straight back to a live image. Gordon Link to post Share on other sites More sharing options...
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