davidrc Posted March 1, 2011 Share #1 Posted March 1, 2011 Advertisement (gone after registration) I've come up against (what will be time honoured for you guys) the issue of lenses that focus shift. Here is my small list so far.....can anyone add to it or remove any? -Voigtlander 35 1.4 -Voigtlander 28 2.0 -Zeiss 50 1.5 -Leica Summilux 35 ASPH -Leica Noctilux 1.0 -Voigtlander Nokton 50 1.1 All help greatly appreciated. David Link to post Share on other sites More sharing options...
Advertisement Posted March 1, 2011 Posted March 1, 2011 Hi davidrc, Take a look here Focus shifting lenses. I'm sure you'll find what you were looking for!
colonel Posted March 1, 2011 Share #2 Posted March 1, 2011 The new Leica Summilux 35mm has apparently almost eliminated the focus shift problem: The NEW Leica 35 Summilux ASPH 1.4 Lens Review | STEVE HUFF PHOTOS I've come up against (what will be time honoured for you guys) the issue of lenses that focus shift.Here is my small list so far.....can anyone add to it or remove any? -Voigtlander 35 1.4 -Voigtlander 28 2.0 -Zeiss 50 1.5 -Leica Summilux 35 ASPH -Leica Noctilux 1.0 -Voigtlander Nokton 50 1.1 All help greatly appreciated. David Link to post Share on other sites More sharing options...
UliWer Posted March 1, 2011 Share #3 Posted March 1, 2011 ...apparently almost eliminated .... Yes, almost ... You will have a certain amount of focus shift in every lens. With most lenses, you won't be able to notice it, with some you will notice it only under laboratory conditions (the newest 35mm Summilux among them), with some you will notice it in practical use (the former 35mm lux for instance). You may try the pre-asph 50mm Summilux or the 90mm Summicron Apo-Asph and may then decide whether they show noticable focus shift in practical use, or just under very painstaking scrutiny. Link to post Share on other sites More sharing options...
ho_co Posted March 1, 2011 Share #4 Posted March 1, 2011 To oversimplify, all lenses with variable aperture will exhibit some focus shift. Faster lenses will exhibit more focus shift, because there's a broader area over which light can enter the lens, and it's the edge rays which are responsible for spherical aberration, the cause of focus shift. Link to post Share on other sites More sharing options...
davidrc Posted March 2, 2011 Author Share #5 Posted March 2, 2011 ahem.... Just the ones you can spot on a practical level guys please....... Link to post Share on other sites More sharing options...
bpalme Posted March 2, 2011 Share #6 Posted March 2, 2011 Mind if I ad to this thread with another question? Can you send your camera and lens to Leica to have it calibrated so there's no focus shift? How much would it cost if so? Link to post Share on other sites More sharing options...
richfx Posted March 2, 2011 Share #7 Posted March 2, 2011 Advertisement (gone after registration) Mind if I ad to this thread with another question? Can you send your camera and lens to Leica to have it calibrated so there's no focus shift? How much would it cost if so? Not really. Focus shift is a characteristic of the lens, not the RF, and does not always manifest itself. It depends on the aperture used, focal distance and other variables. Rich Link to post Share on other sites More sharing options...
bpalme Posted March 2, 2011 Share #8 Posted March 2, 2011 Not really. Focus shift is a characteristic of the lens, not the RF, and does not always manifest itself. It depends on the aperture used, focal distance and other variables.Rich Thanks. But can you send the lens itself in to be adjusted so it's minimal shift? Link to post Share on other sites More sharing options...
andybarton Posted March 2, 2011 Share #9 Posted March 2, 2011 No, it's inherent in the lens design. Link to post Share on other sites More sharing options...
ezc203 Posted March 2, 2011 Share #10 Posted March 2, 2011 bpalme - I have heard of people adjusting their lenses to be optimized at particular apertures. If this what you are trying to ask? I have never does this myself because I don't deem it a practical solution. Link to post Share on other sites More sharing options...
bpalme Posted March 2, 2011 Share #11 Posted March 2, 2011 Ok thanks. Link to post Share on other sites More sharing options...
tdtaylor Posted March 2, 2011 Share #12 Posted March 2, 2011 bpalme- for example, with the original 35Lux ASPH, Leica would set optimum focus at 1.4 or 2 if requested. It did't get rid of it, just "pushed" the focus shift to other apertures. If one does a lot of close photography, it becomes much more obvious as the depth of field becomes shallower- a reason many noticed it more than others. Had a friend with a 35lux that "didn't have shift, a good copy," until I had him try it at several apertures at minimum focus- it shifted like mine. Of course back or forward focusing of the camera just complicates the issue . Link to post Share on other sites More sharing options...
Etruscello Posted March 6, 2011 Share #13 Posted March 6, 2011 From personal experience, I can add two focus shifting lenses to the list: The 35mm Summilux pre-ASPH and the 75mm Summilux. In both cases the shift is slight. The beauty of their wide-open bokeh is such that I seldom want to use them off of f1.4, hence focus shift is not an important issue for me -- in regard to these lenses. I do make sure that my M bodies are calibrated for spot-on wide-open focus performance. Tom P. Link to post Share on other sites More sharing options...
Etruscello Posted March 6, 2011 Share #14 Posted March 6, 2011 P.S. In general, I do not find focus shift to be a big problem. I simply compensate from f2 to f4 for the very fast lenses. After f4, depth-of-field does an adequate job. There are 2 ways to compensate for focus shift. In general, simply turn the focus ring 1 smidge to the right (toward the VF window) after you have mechanical focus. This will do the trick over 95% of the time. (A smidge is the shortest controlled turn you are able to make easily.) For critical situations, focus bracket -- easy on a digital M because of the immediate feedback. Remember, with a RF, focus always needs some form of focus compensation, regardless of the lens. This is true because we often have to focus on an off-center subject and then recompose. Recomposition changes the focus plane; therefore, we must often resort to "smidge" compensations in fast breaking situations or focus bracketing in static situations. Tom P. Link to post Share on other sites More sharing options...
pico Posted March 6, 2011 Share #15 Posted March 6, 2011 I do make sure that my M bodies are calibrated for spot-on wide-open focus performance. Tom P. I thought the lenses were adjusted for focus-shift rather than the camera. Link to post Share on other sites More sharing options...
lct Posted March 6, 2011 Share #16 Posted March 6, 2011 Some lenses suffer focus shift on brick walls but not in day to day use, i don't know why. Link to post Share on other sites More sharing options...
Etruscello Posted March 6, 2011 Share #17 Posted March 6, 2011 Pico -- My understanding is that the camera can be adjusted to make sure that fast lenses which are used on it wide-open do not back or front focus. Focus shift (the loss of perfect focus as one stops down from wide-open) cannot be adjusted in the camera -- it is a property inherent in the lens. It's my experience that DAG can make a focus-shifting lens look better by adjusting the camera to front-focus slightly for fast lenses, wide-open. Such lenses then tend to move into good focus for the next 2 stops or so as they are stopped down. Tom P. Link to post Share on other sites More sharing options...
k-hawinkler Posted March 7, 2011 Share #18 Posted March 7, 2011 I just sent in my 5 cm Rigid Summicron. No focus wide open, stopped down focused well enough. Is this just a particular adjustment issue with my lens or is the lens known for having a substantial focus shift? Thanks, K-H. Link to post Share on other sites More sharing options...
DOUG66 Posted March 8, 2011 Share #19 Posted March 8, 2011 The attached graphs may be of interest. I corrected my 50mm Summicron which was backfocussing on my M8 although focussing OK on my M6, by replacing the the original shim collar with one which was 125 microns (.005inch) thicker. It can be seen from the graphs that focus shift with F number is a charachteristic of this lens but when adjusted for the M8 is not a serious problem. What is interesting is the graph of a 1932 elmar, it is no wonder that Leica made a name for quality with those original cameras. Doug. 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/145369-focus-shifting-lenses/?do=findComment&comment=1610433'>More sharing options...
k-hawinkler Posted March 9, 2011 Share #20 Posted March 9, 2011 Hi Doug, Many thanks. Very interesting. Could you please explain to me why the curve for the 50 Summicron didn't just move up, but changed its shape, when you replaced the shim. Best, K-H. Link to post Share on other sites More sharing options...
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