christer Posted August 16, 2010 Share #21 Posted August 16, 2010 Advertisement (gone after registration) Would be interesting to see if the shift carries over to more commomly used distances such as 5 feet, 2 meters, and more. At 2 meters and more accurate focusing with the rangefinder becomes difficult if you are focusing on a yardstick. Even if you use a focusing aid (a simple stick standing vertically at the target distance will do) it is difficult with .72 viewfinders and smaller. Anyway this is not so much a problem for me, I am shooting film ;-) Link to post Share on other sites More sharing options...
Advertisement Posted August 16, 2010 Posted August 16, 2010 Hi christer, Take a look here focus shift on fast voigtländer lenses. I'm sure you'll find what you were looking for!
Guest zoz Posted August 16, 2010 Share #22 Posted August 16, 2010 If you have shot the rule 4x with 4 lenses, then I would have thought that 4 images would have been fine. I did not make this image for this forum ... If You like it different do so... I do things the way I like them to do and for me it is more convenient to scroll. I will not make extra images to post them in this forum because of some restrictions in forum rules. I have no time for such nonsense. The consequence for me is not to show them here. Link to post Share on other sites More sharing options...
bill Posted August 16, 2010 Share #23 Posted August 16, 2010 I will not make extra images to post them in this forum because of some restrictions in forum rules. I have no time for such nonsense. The consequence for me is not to show them here. How to win friends and influence people... Fine by me. Lateral scrolling is a pain in the arse, as any right-thinking person knows. Now leave those poor rulers alone and go and shoot something sensible, eh? Regards, Bill Link to post Share on other sites More sharing options...
01af Posted August 16, 2010 Share #24 Posted August 16, 2010 ... I find it humorous when they pull out all of their winter gear if it drops lower than 55 degrees F. 55° F ... what is it in real degrees? Link to post Share on other sites More sharing options...
250swb Posted August 16, 2010 Share #25 Posted August 16, 2010 For myself I have had some CV lenses with noticable aperture related focus shift, but I can't detect any with my Nokton f1.1, so I'm not in the contradiction group, more the sample variation lobby. This is the problem with photographing rulers zoz, it doesn't always pan out across the board. Steve Link to post Share on other sites More sharing options...
bill Posted August 16, 2010 Share #26 Posted August 16, 2010 Don't you come around here with your centipedes and stuff. Nothing wrong with feet'n'inches, even if the Yanks have never got the idea of a gallon. Regards, Bill Link to post Share on other sites More sharing options...
bill Posted August 16, 2010 Share #27 Posted August 16, 2010 Advertisement (gone after registration) This is the problem with photographing rulers zoz, it doesn't always pan out across the board. Maybe protractors would be better then...? Regards, Bill Link to post Share on other sites More sharing options...
Guest zoz Posted August 16, 2010 Share #28 Posted August 16, 2010 Now leave those poor rulers alone and go and shoot something sensible, eh? What Do You think why I made this boring ruler images? Because I detected problems and I want to find out if it is me or the equipment... Seeing the result I thought this could be interesting for other people, but it seems there are more people who care about scrolling images and philosophy of ruler photography. Ok, got my lesson I will keep my stuff in the future! Link to post Share on other sites More sharing options...
andybarton Posted August 16, 2010 Share #29 Posted August 16, 2010 No need to get upset about things. All I did was to ask you to consider other forum members in future. Thanks. Link to post Share on other sites More sharing options...
Guest zoz Posted August 16, 2010 Share #30 Posted August 16, 2010 Lateral scrolling is a pain in the arse, as any right-thinking person knows. Not reached the second dimension yet? Be aware there are (at least) three in real life! Link to post Share on other sites More sharing options...
chrism Posted August 16, 2010 Share #31 Posted August 16, 2010 Calm down, children. We understand the need for rules, and at the same time we can appreciate the original poster's efforts to show focus shift - which he does clearly (and to a worrying degree) in his images. Perhaps we should be talking about how common this phenomenon is as a practical issue? All lenses will have some, but it's obvious that the last 35 'Lux wasn't the only one to have it to a degree where it impinges on the ability to rely on a seemingly well-focussed photograph disappointing. I'm afraid I tend to use the Summarits for the most part these days, and only get out the Luxes when I want the f1.4, so it doesn't worry me greatly. I shall try to resist any brief desires I feel towards pointing the Summarits towards a ruler! Chris Link to post Share on other sites More sharing options...
Guest zoz Posted August 16, 2010 Share #32 Posted August 16, 2010 I shall try to resist any brief desires I feel towards pointing the Summarits towards a ruler! Do it, I am quite sure You will not find anything worrying. And if, it is better to see a problem clearly. The Ultron has got a really brutal focus shift. Knowing this it´s now giving me satisfactory results. I avoid f2 and f4 and use f2.4 and f5,6 instead to get tack sharp images, which was not the case before I found out about the problem. Link to post Share on other sites More sharing options...
Guest zoz Posted August 16, 2010 Share #33 Posted August 16, 2010 At 2 meters and more accurate focusing with the rangefinder becomes difficult if you are focusing on a yardstick. Even if you use a focusing aid (a simple stick standing vertically at the target distance will do) it is difficult with .72 viewfinders and smaller. Anyway this is not so much a problem for me, I am shooting film ;-) Focus shift is at larger distance growing (like dof). The problem is not changing there. Even at infinity the lenses are not sharp when stopped down a little bit and set to infinity. Why do You think this is no issue for analogue photography? Link to post Share on other sites More sharing options...
01af Posted August 17, 2010 Share #34 Posted August 17, 2010 Lateral scrolling is a pain in the arse, as any right-thinking person knows. It's a PITA for pictures ... but not for a test shot like Steffen's. Of course it still is against the forum rules, and arranging the test images in a column rather than a row would have been just as fine. By the way, what ARE the forum rules regarding maximum image width? Ok, got my lesson I will keep my stuff in the future! Puleez ... don't act childish. You haven't been banned, your test imge hasn't been deleted—you just have been asked to stick to the rules in the future. And now for one of Steffen's more surprising results: Has anyone noticed how extraordinarily small the focus shift in the Nokton 35/1.2 is? At f/2 and f/2.8, the increasing DOF extends mostly towards the background and hardly towards the foreground which means some focus shift is present. But there's no point on the ruler that actually loses sharpness due to stopping down. Look at the '17' at f/1.1 and f/2 in the Nokton 50/1.1, or at the '20' at f/2 and f/4 in the Ultron 28/2 for a comparison; there you'll see how focus shift can deteriorate sharpness in areas that are supposed to sharpen up when stopping down. No such effect in the Nokton 35/1.2! A surprising result. Now I am wondering if that's typical for this lens. Can other owners verify this? Link to post Share on other sites More sharing options...
andybarton Posted August 17, 2010 Share #35 Posted August 17, 2010 The max dimension for shots on the forum is 960 pixels. Link to post Share on other sites More sharing options...
Guest zoz Posted August 17, 2010 Share #36 Posted August 17, 2010 And now for one of Steffen's more surprising results: Has anyone noticed how extraordinarily small the focus shift in the Nokton 35/1.2 is? At f/2 and f/2.8, the increasing DOF extends mostly towards the background and hardly towards the foreground which means some focus shift is present. But there's no point on the ruler that actually loses sharpness due to stopping down. Look at the '17' at f/1.1 and f/2 in the Nokton 50/1.1, or at the '20' at f/2 and f/4 in the Ultron 28/2 for a comparison; there you'll see how focus shift can deteriorate sharpness in areas that are supposed to sharpen up when stopping down. No such effect in the Nokton 35/1.2! A surprising result. Now I am wondering if that's typical for this lens. Can other owners verify this? That the DOF is growing more to the background than to the foreground is normal. I would say there is no (noticeable) focus shift with the 1,2/35 Nokton. This is matching what Sean Reid wrote in his post I linked in the starting post and some of his reviews. But he stated that the 1,5/50 would have "no or little focus shift" too, what is contrary to what I find, or we have different definitions of "little", what is possible, because the shift is definitively smaller than with other lenses. Steve can´t find any focus shift on his 1,1/50. So there might be a sample variation. Steve, have You joined the club of sophisticated ruler photography , or is this experience in real life? The focus shift of the Ultron was so strong that i stumbled over it in normal use. The one of the Noktons was not so easy to see. If I find that an image I made is not correctly focussed (and we are talking about only few cm) I´m firstly blame this on me, what is correct in most cases!. It took a while to see that images with wide open lens are more often spot on, and images made stopped down a little are not. Link to post Share on other sites More sharing options...
ziggurat Posted August 17, 2010 Share #37 Posted August 17, 2010 Hello, I've read several threads about focus shift all centered around rangefinder lenses. Is this a potential problem for all lenses or are other lens designs/systems less prone for some reason? Just curious as I've gone Dig 1,2 and three so far then Canon 5DMk 2 while waiting to see what may come out at Photokina. I'm seriously considering moving to an M but issues like this are not something I look forward to dealing with. Kind of hoping for an optical/electrical viewfinder system but would focus shift still be an issue? Thanks Johnny Link to post Share on other sites More sharing options...
Guest zoz Posted August 17, 2010 Share #38 Posted August 17, 2010 Hello, I've read several threads about focus shift all centered around rangefinder lenses. Is this a potential problem for all lenses or are other lens designs/systems less prone for some reason? Just curious as I've gone Dig 1,2 and three so far then Canon 5DMk 2 while waiting to see what may come out at Photokina. I'm seriously considering moving to an M but issues like this are not something I look forward to dealing with. Kind of hoping for an optical/electrical viewfinder system but would focus shift still be an issue? Thanks Johnny Focus shift is a problem that is not related to the rangefinder but to wide opened lenses. The outer parts of the aperture focus somewhere different than the inner part. ("spherical aberration"). Afaik the Canon 1,2/50 is also showing focus shift, but there will be others too. AF-Systems are theoretical able to compensate focus shift (I´m not shure if they do). Focussing in Live-View with stopped down lens will show no focus shift. If the camera is focussed in Live-View / contrast AF with open lenses focus shift will be an issue. Link to post Share on other sites More sharing options...
gyoung Posted August 17, 2010 Share #39 Posted August 17, 2010 And what would be the point of that? If you have shot the rule 4x with 4 lenses, then I would have thought that 4 images would have been fine. Speaking personally, I would prefer the original presentation even if I have to scroll across, its then easier to compare. Perhaps the 'rules' were designed for 'normal' pictures where you would expect to see the whole image without scrolling. As far as the tests are concerned, it just proves that its impossible to design a lens to do everything well, an f/1.0 lens that does well with black cats in coal cellars, panoramic views on a sunny day and close ups of gnats nether regions would be lovely but the laws of optics and physics intervene to make the ideal unatainable even to Leicas lens designers (probably the best on 35mm optics IMHO) never mind the lesser mortals, of whom Voigtlander is probably better than most. Although I gather software can do wonders with digital stuff to make a silk purse out of a sows ear. I have a 28mm Ultron (the older f/1.9), it gets used pretty well all the time at f/1.9 or 2.8 for available light interiors, thats what I got it for. It does alllright for the occasional view at 5.6 if I feel the need but I dont particularly like the angle of view so would use the 35 Summicron or 21 Elmarit, which presumably behave better, these observations are subjective, if I don't see a problem I don't bother looking for one! Likewise the 50mm Summilux and Summicron I have work well at full aperture when necessary and stopped down to 5.6 or 8 at other times. In all these cases depth of field presumably masks any focus shift the lens may have. If I want very small apertures or good performance at high magnifications I would use a symetrical lens design of (necessarily) smaller aperture such as the Elmar, or the macro lenses where focus shift and difraction are more easily controlled, not a lens designed for totally other situations. Horses for courses, I wouldn't go shopping in a Ferrari even if I had one Gerry, who remembers swotting Cox's Optics for C&G Photography a long time ago! Link to post Share on other sites More sharing options...
01af Posted August 17, 2010 Share #40 Posted August 17, 2010 AF systems are theoretically able to compensate focus shift (I'm not sure if they do). In theory, an auto-focus could indeed compensate for focus shift but in practice it would ask too much of precision from the AF systems ... in real life, a focus shift compensation is likely to cause more problems than it would solve. So I am not aware of any AF system that actually tries to compensate for focus shift. Most users of AF systems are so used to slight focussing inaccuracies anyway that they simply don't notice focus shift as an issue of its own. Aperture-related focus shift appears as a problem in the Leica M system because the lenses and the rangefinder focussing are so precise, the focus shift problem will stand out. But in fact, it's a general problem in all fast lenses, particularly standard and wide-angle, less so in telephoto lenses. The latest Leica M Asph lenses are designed to minimize focus shift issues. Link to post Share on other sites More sharing options...
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