IkarusJohn Posted February 4, 2015 Share #41 Posted February 4, 2015 Advertisement (gone after registration) This basically confirms what I've seen recently on my 35 FLE as well. It seems to focus perfectly wide open at f/1.4 with the rangefinder. When I stop it down however it seems to back focus ever so slightly. This is noticeable even at f/2, and becomes more noticeable at f/2.8. It's noticeable up until f/8 where I can't detect it any more. This happens at all distances. If I compensate for back focus (just like if the rangefinder was back focusing) by slightly focusing past the subject my subject (in the center) is in proper focus again. If it's back focussing, don't you want to focus slightly in front? Link to post Share on other sites More sharing options...
Advertisement Posted February 4, 2015 Posted February 4, 2015 Hi IkarusJohn, Take a look here Tim Ashley - 35mm FLE review. I'm sure you'll find what you were looking for!
indergaard Posted February 4, 2015 Share #42 Posted February 4, 2015 If it's back focussing, don't you want to focus slightly in front? Yes, which is what I need to do, unless I'm at f/1.4 or at f/8. Between f/2 and f/5.6 the center of the image goes slightly out of focus, and the plane of focus is moved backwards. Towards the edges however, on planar subjects, the subject will be in focus again. It's quite strange, and very frustrating, but very easy to reproduce with a planar subject with fine texture, a tripod and the EVF. This does not happen with my Lux 50 at all in the center. It is also known to have field curvature, but the center always stays sharp no matter what f-stop I use it at. The 35 FLE exhibits a big variance in center resolution, at least on my copy - except at f/1.4 and f/8 and up. At f/2.8 I have to focus very slightly closer to the subject to actually get the center in focus. At f/1.4 I don't have to compensate at all however, which is what I find to be a little bit strange. Link to post Share on other sites More sharing options...
colonel Posted February 4, 2015 Share #43 Posted February 4, 2015 Yes, which is what I need to do, unless I'm at f/1.4 or at f/8. Between f/2 and f/5.6 the center of the image goes slightly out of focus, and the plane of focus is moved backwards. Towards the edges however, on planar subjects, the subject will be in focus again. It's quite strange, and very frustrating, but very easy to reproduce with a planar subject with fine texture, a tripod and the EVF. This does not happen with my Lux 50 at all in the center. It is also known to have field curvature, but the center always stays sharp no matter what f-stop I use it at. The 35 FLE exhibits a big variance in center resolution, at least on my copy - except at f/1.4 and f/8 and up. At f/2.8 I have to focus very slightly closer to the subject to actually get the center in focus. At f/1.4 I don't have to compensate at all however, which is what I find to be a little bit strange. Leica lenses are always optimised to focus wide open. the reason it goes out between f2.8 and f5.6 is focus shift. the dof at f8 (or f5.6) compensating Link to post Share on other sites More sharing options...
indergaard Posted February 5, 2015 Share #44 Posted February 5, 2015 Leica lenses are always optimised to focus wide open. the reason it goes out between f2.8 and f5.6 is focus shift. the dof at f8 (or f5.6) compensating But the 35 FLE isn't supposed to have very easily noticeable focus shift? Link to post Share on other sites More sharing options...
colonel Posted February 5, 2015 Share #45 Posted February 5, 2015 But the 35 FLE isn't supposed to have very easily noticeable focus shift? True, but it does have and maybe it varies per copy It seems from the comments here it's not an isolated case I just read the digilloyd review of 35mm lens and it's very interesting. He is a bit too gung ho for the Zeiss but his tests do reveal focus shift with the summicron and, albeit less, with the summilux Link to post Share on other sites More sharing options...
indergaard Posted February 5, 2015 Share #46 Posted February 5, 2015 True, but it does have and maybe it varies per copyIt seems from the comments here it's not an isolated case I just read the digilloyd review of 35mm lens and it's very interesting. He is a bit too gung ho for the Zeiss but his tests do reveal focus shift with the summicron and, albeit less, with the summilux Well, to compensate for the amount of focus shift I am experiencing I have to move the focus ring about 2-3 mm on the barrel for the subject to be in proper focus at apertures f/2 to f/5.6 - in the center of the image. That is not mild focus shift in my opinion. The strange thing is though that I have not noticed this before I got my camera back from service/calibration. I guess I should send Leica CS an email about this and see what they say. Link to post Share on other sites More sharing options...
elmars Posted February 5, 2015 Share #47 Posted February 5, 2015 Advertisement (gone after registration) See the pictures below: Summilux 35 FLE, extreme cropping, all the same distance (ca. 1,2 m), no focussing between the shots. First f 1,4, then f 2,0, then 2,8, then 4,0. Elmar Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/202466-tim-ashley-35mm-fle-review/?do=findComment&comment=2759576'>More sharing options...
horosu Posted February 5, 2015 Share #48 Posted February 5, 2015 I do a lot of shots of planar subjects nowadays, so I'm considering selling the FLE and getting a used Summicron 35 ASPH instead. The thread I started about the issue: http://www.l-camera-forum.com/leica-forum/leica-m-lenses/362339-summilux-35-fle-focusing-issues.html The ZM Distagon may suit you more, for this type of photography Link to post Share on other sites More sharing options...
indergaard Posted February 5, 2015 Share #49 Posted February 5, 2015 See the pictures below: Summilux 35 FLE, extreme cropping, all the same distance (ca. 1,2 m), no focussing between the shots. First f 1,4, then f 2,0, then 2,8, then 4,0. Elmar Thanks. I'll try to replicate this test later today myself and post some results. My results are definitely like that. Link to post Share on other sites More sharing options...
indergaard Posted February 5, 2015 Share #50 Posted February 5, 2015 The ZM Distagon may suit you more, for this type of photography I know, but size wise it's a little bit too big. The 35 FLE without the hood is size-wise more in line with what I want. Link to post Share on other sites More sharing options...
horosu Posted February 5, 2015 Share #51 Posted February 5, 2015 I know, but size wise it's a little bit too big. The 35 FLE without the hood is size-wise more in line with what I want. Then, my second suggestion would be he 35/2 Biogon: great handling, even plane of focus and no focus shift Link to post Share on other sites More sharing options...
indergaard Posted February 5, 2015 Share #52 Posted February 5, 2015 I did some quick tests with the lens to illustrate my findings. I put the camera on a tripod and used a very simple but textured subject. I focused the camera with the rangefinder at a distance at about 1.2 meters. I used ISO 200 with the self-timer and I didn't touch the focusing mechanism of the lens between the shots, I simply changed apertures and took a new shot with the self-timer. I made two shots, one at f/1.4 and one at f/2.8. The first two shots was focused correctly according to the rangefinder. The last two shots was focused wrong (focused past the point of focus to correct for rearward focus shift). I focused about 1-2 mm past the point of focus on the lens barrel itself by moving it 1-2mm further than the point ot focus. I focused on the letter l on all images. As you can see the f/1.4 image when correctly focused looks decent for f/1.4 (these images are about 150% image view and all sharpening has been disabled). Stopping it down to f/2.8 doesn't really do anything, except if you notice on the right where the wall is you can clearly see that the point of focus on the f/2.8 image is actually behind the subject that should be in focus (the letter l). The texture and the writing does not improve by stopping the lens down from f/1.4 to f/2.8. On the two images that I intentionally focused wrong (to compensate for rearward shift) you can see that the f/1.4 shot looks slightly worse - as it should be, since the camera is actually misfocused. But on the f/2.8 image the texture and letters really clear up and look properly in focus, even though the camera is misfocused. Focused correctly at f/1.4: Focused correctly at f/2.8: Focused wrong at f/1.4: Focused wrong at f/2.8: So as I stop the lens down the lens clearly exhibits what I would say to be a lot of focus shift. Shooting subjects in the center of the image at f/2-f/5.6 basically means that the plane of focus is always behind the subject by a big and very noticeable margin, but at f/1.4 the plane of focus is where it should be. Is this normal with this lens to this degree? I can't imagine that it can be normal. I repeated the same test on my Summilux 50 ASPH and the results from the 50 is as it should be. Focused correctly at f/1.4 and stopping down at f/2.8 improves the resolution and sharpness of the subject as it should be. Compensating for rearward focus shift by the same amount as I did on the 35 FLE makes the lens worse at every aperture, and it never improves. Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted February 6, 2015 Share #53 Posted February 6, 2015 As always with focusing issues and Leica M it's a matter of calibration of the Body and or the lens. And with the FLE Floating Lens Element lenses the calibration of that part of the lens has to be performed as well to make sure the close range correction works as intended. My sample of the 35mm 1.4 Asph FLE doesn't have focus issues. Send the lens in for calibration is my advice. Link to post Share on other sites More sharing options...
pgk Posted February 6, 2015 Share #54 Posted February 6, 2015 And with the FLE Floating Lens Element lenses the calibration of that part of the lens has to be performed as well to make sure the close range correction works as intended. My sample of the 35mm 1.4 Asph FLE doesn't have focus issues. Absolutely! If the FLE mechanical mechanism is incorrectly adjusted it might well give rise to all sorts of problems which might include exaggerated image curvature, focus drifts and inaccurate focus. I actually now own two Floating Element design lenses the 50 Summilux Aspheric and the 75mm Summicron. Both are well adjusted and the 75mm is as well adjusted as I could possibly want, but it is my second copy, the first was really awful, and I suspect that both focus and the FLE mechanism were well out of tolerance. RF requires mechanical near perfection, something there is a tendency to forget. Given that the 35mm FLE is a design update intended to deal with focus shift I would expect it to do so - and if not I would have Leica check and recalibrate it. FWIW my non-FLE version shows very little (and for practical purposes none that I've noticed) focus shift. Perhaps I'm simply fortunate in having a copy in which tolerances and adjustment are all as good as they can be. Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted February 6, 2015 Share #55 Posted February 6, 2015 I also had the 35mm 1.4 Asph (Non FLE) and sold it. It had very little focus shift, but the design with the aperture ring so close to the lens hood and the lens hood comming off by just a small bump I decided to upgrade and really enjoy the new FLE version. The aperture ring stopping indentation is a little too loose to my liking so I'm gonig to have that adjusted. To achive nice back ground Bokeh I have to be very carefull when prost processing the images but I'm used to that. Link to post Share on other sites More sharing options...
apertur Posted February 6, 2015 Share #56 Posted February 6, 2015 Hi, I had 4 FLEs. They all were frustrating and calibration did not help. One was very soft in the middle at f4 while the edges were fine. Very odd. One was OK close but lost focus with more distance. Ultimately, a visit in Wetzlar was the fix. They replaced it and said that calibration was not possible with the one I had. Now all is fine. This is a fantastic lens. Yes there is Focus Shift but really minor. Nothing to worry about. Link to post Share on other sites More sharing options...
indergaard Posted February 6, 2015 Share #57 Posted February 6, 2015 Thanks for the replies guys. I just sent an email to Leica CS about the issue, and also attached a link to my post here on this forum. Waiting for their response on what to do. I can't really use this lens for anything as it is now. It works fine at f/1.4 and f/8 but that's about it. If this behavior is normal then I'm definitely selling it and getting a Zeiss Biogon T* 35mm f/2 instead. Link to post Share on other sites More sharing options...
jrh68uk Posted February 6, 2015 Share #58 Posted February 6, 2015 I can assure you it's not normal behaviour. Reading this and the related thread caused me to test mine. Seemed like a good idea as it's new (to me) and I hadn't done any detailed testing to check for focus shift because I assumed there would be little to none. I had tested my Summicron 35 ASPH for the same, some time ago, because of what I was seeing in real pics, and confirmed that it does, indeed, rear-focus when stopping down but to an extent that's acceptable once I had the lens adjusted with my M Typ240. My FLE does not have any focus shift, at all, or at least that I can detect. If I were to measure it with millimetre scales I might find that the area of maximum sharpness would extend very slightly backward more than it does forward, as the aperture is closed, or I might not. What I can say is that, if I focus using the RF, what I want to be sharp stays sharp, no matter what aperture I'm using. Close up or distant. I'm lucky because it seems to be perfectly calibrated to my M, despite the fact that I've not sent it (or the M back) in for adjustment. The M was, however, recently calibrated against three of my other lenses, so I know it's OK. I would send the lens in and don't give up on it, because this has to be the best thing since sliced bread. Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted February 6, 2015 Share #59 Posted February 6, 2015 ...I might find that the area of maximum sharpness would extend very slightly backward more than it does forward... This is also quite normal for most lenses to behave like this. DOF expands. But peak sharpness (Depth of Sharpness) should remain at the focused distance. Link to post Share on other sites More sharing options...
DMJ Posted February 6, 2015 Share #60 Posted February 6, 2015 Out of interest anyone know where Tim Ashley has gone too? His blog just seemed to stop on his website & nothing on here for a while. Hope he's ok. Link to post Share on other sites More sharing options...
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