Guest willjanurgucken2000 Posted April 26, 2010 Share #1 Posted April 26, 2010 Advertisement (gone after registration) Hi! I've an 35mm CV on a M8. Surprise surprise, it has a appreciable focus shift. but ok, it was only from f 2.8 till f4. At 5.6 it was away (depth of field), at f 1.4 the lens is tack sharp. so long, i was happy. then by changing the lens I dropped the 35mm and it was heavily out of focus. I brought it to my local repairman who fixed the lens. He told me that he fixed the back focus (from the crash) and also the focus shift. now the lens does not shift any more - really. for the first time in my life I tested a lens with a tripod and taking pictures from walls, bookcases.... and yeah the focus shift is away. BUT: If I focus now on a subject far away (infinity) the rangefinder says one millimeter before infinity on the lens, that its sharp. do you understand what I try to say (sorry, my english is fu**ing bad). Is this normal, bad, or what are the consequences. important is, that the focus shift between 2.8 und 4 is away... regards will Link to post Share on other sites More sharing options...
Advertisement Posted April 26, 2010 Posted April 26, 2010 Hi Guest willjanurgucken2000, Take a look here Fixing focus shift?!. I'm sure you'll find what you were looking for!
jaapv Posted April 26, 2010 Share #2 Posted April 26, 2010 Focus shift correction is always a compromise. It seems the technician adjusted the lens to be more or less within DOF throughout the range, and I think you will have to accept the discrepancy at infinity if you are happy with that.. It is not my favorite adjustment, I prefer a lens to be spot-on wide open, which means it will be off between f2 and 5.6, after which DOF kicks in, but that is just me. Link to post Share on other sites More sharing options...
Guest willjanurgucken2000 Posted April 26, 2010 Share #3 Posted April 26, 2010 thank you for the fast answer. It is still tack sharp wide open. It only seems that the focus shift has been forwarded to f8 and f11, so that the DOF covers the focus shift. it's the only way how I can explaine it to me... from up f 1.4 I cant see any shift and therefore it is still sharp... and I also can't notice any difference in the infinity position. Link to post Share on other sites More sharing options...
jaapv Posted April 26, 2010 Share #4 Posted April 26, 2010 As I say, if it works best for you this way, keep it that way. Link to post Share on other sites More sharing options...
!Nomad64 Posted April 26, 2010 Share #5 Posted April 26, 2010 Well, at this stage I'd think that the best way to fix a lens' focus shift is dropping it and have it repaired. As an added benefit one ends with an enhanced lens that can focus beyond infinity :-) Apart from kidding, my suggestion is to keep the lens as is. Probably the focus shift is still there, but the drop and the fix somehow "shifted" it at infinity. If you can focus at all distances within the cam's reach it's OK. After all the annoyance comes only from the awareness that the rangefinder's and lens barrel's infinities do not exactly match, but as long as the pictures are sharp why bothering yourself? Cheers, Bruno Link to post Share on other sites More sharing options...
Guest mc_k Posted April 29, 2010 Share #6 Posted April 29, 2010 ...BUT: If I focus now on a subject far away (infinity) the rangefinder says one millimeter before infinity on the lens, that its sharp. do you understand what I try to say (sorry, my english is fu**ing bad). Is this normal, bad, or what are the consequences. important is, that the focus shift between 2.8 und 4 is away... ... yes, if your lens was adjusted to front-focus slightly to compensate for focus shift, the discrepancy in the scale will be as you described. Link to post Share on other sites More sharing options...
Islandmike Posted May 2, 2010 Share #7 Posted May 2, 2010 Advertisement (gone after registration) If I have a problem with focus shift, I reckon it's usually in my legs. Can anyone stand that still as to be sure of a sharp shot at f/1.5? Link to post Share on other sites More sharing options...
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