arthury Posted January 27, 2007 Share #21 Posted January 27, 2007 Advertisement (gone after registration) Arthur, that is reasonable - but is this possible? I still do not understand how a camera is adjusted to each lens when the focus errors of the different lenses vary, unless there is also some asjustment that can be made on the lenses. If I can understand the possibilities here, I would be inclined to do exactly what you recommend. Bill Just a wild guess ... and the possibility is small but it can happen ... I believe you that there's a focus issue based purely on the door-knob image you posted. About the variations in focus errors, here are the possible causes which came to mind: tester's error : which is highly probable using that 45 deg test and rangefinder camera. Were you using a magnifier? I, for one, cannot certainly guarantee my tests and adjustments are exactly the same for every test. The mounts on the lenses are imperfect The mount on the M8 is imperfect It's very hard to hold the (1) static for every test when we're basing it on our eyes and hand adjustments. If (2) and (3) exists in different combinations, it will certainly confuse the heck out of you. If the tests are done in the lab with precise instrumentations and automated testing, many variables can be held static to hunt down the cause(s) of the focusing errors. Just curious: are the rest of the lenses failing the door-knob test as well? Seems like the door-knob test is more reliable to me: it's crude but revealing. Link to post Share on other sites More sharing options...
Advertisement Posted January 27, 2007 Posted January 27, 2007 Hi arthury, Take a look here Back focus adjustment question.. I'm sure you'll find what you were looking for!
robsteve Posted January 27, 2007 Share #22 Posted January 27, 2007 Bill: In the past Leica would fine tune a lens and camera combination. I don't know if they can fine tune a bunch of lenses to a single camera. I think Jim Marshall was famous for having a body for each lens and getting Leica to match them perfectly. Link to post Share on other sites More sharing options...
Shootist Posted January 27, 2007 Share #23 Posted January 27, 2007 The focusiing on any Leice M, and any rangefinder, is mechanical with many moving parts. That includes the arm and wheel that are visible inside the body, parts inside the rangefinder that are not visible and the ring on the lens. As the lens focusing ring is moved the ring at the back of it moves in or out, pushing the wheel on the arm inside the camera in or out. Which in turn move the arm and the rangefinder. If any one of these get out of adjustment it will cause either the whole camera to not focus correctly with any lens or just that lens to not focus correctly. I have some images of this that I will post shortly. Link to post Share on other sites More sharing options...
Shootist Posted January 27, 2007 Share #24 Posted January 27, 2007 Here are some photos of a M3 rangefinder internal mechanism. First is with wheel fully out and second is with it fully in. See how the part with the knurled wheel moves back when the wheel is fully pushed to the back. Sorry I could upload them. they are slkightly bigger then the sire allows Go to. SmugMug - Ed Chatlos (Shootist) : Focus Test To view them. The second 2 are with a 50mm lens at closest focus and infinity. Shots taken with Nikon D200 & 105 Micro VR. Link to post Share on other sites More sharing options...
carstenw Posted January 27, 2007 Share #25 Posted January 27, 2007 Rob, do the markings on that photo agree with your knowledge of the adjustment? I thought that the third screw at the back was the one for close focus adjustment? Link to post Share on other sites More sharing options...
robsteve Posted January 27, 2007 Share #26 Posted January 27, 2007 Rob, do the markings on that photo agree with your knowledge of the adjustment? I thought that the third screw at the back was the one for close focus adjustment? Carsten: The one marked near focus is the correct one. In the case of the near focus, the screw is not making the adjustment, but the screw is loosened and the tab on the eccentric behind the screw is moved to make the adjustment, then the screw is tightened again. This is the adjustment I suggest people don't play with and even in my manual it mentions it is seldom off. I don't know what the third screw is for, I might have to look it up in my manual. I suspect it may have something to do with the parralex correction of the finder frames. Robert Link to post Share on other sites More sharing options...
carstenw Posted January 27, 2007 Share #27 Posted January 27, 2007 Advertisement (gone after registration) Another related question: on the MP, there is no Leica dot. Is that what the screw on the front replaces, to give access to the vertical offset adjustment? I am still toying with the idea of trying out the near focus adjustment. If I have to send the camera back to Leica anyway, I don't see the harm in seeing if I can get it right myself. This ability sure would come in handy in the future. Link to post Share on other sites More sharing options...
Shootist Posted January 27, 2007 Share #28 Posted January 27, 2007 Another related question: on the MP, there is no Leica dot. Is that what the screw on the front replaces, to give access to the vertical offset adjustment? I am still toying with the idea of trying out the near focus adjustment. If I have to send the camera back to Leica anyway, I don't see the harm in seeing if I can get it right myself. This ability sure would come in handy in the future. Yes that is it. Removing that screw allows you to insert a small screw driver to make that adjustment. Watch out though that screw is very small and only has a few threads on it. Like 3/4 or one turn on it and it is out. Took me hours to find it the first time I removed it. Link to post Share on other sites More sharing options...
lovelyleica Posted January 28, 2007 Share #29 Posted January 28, 2007 I don't know why a M camera body can be so "unprecisely" adjusted when it is new and has just left the factory. My explanation would be that a M camera and especially its rangefinder is a highly precise arrangement of metal pieces that have to "live" together for a certain time to find there definite place. Rangefinder precision is entirely due to micrometric movements of metal pieces one against the others. Any M camera I had in the past had to be adjusted after first use, but then, they could stay perfectly adjusted for a pretty long time, because of the highest quality of the materials used in Leica cameras. A rangefinder system needs to have camera AND lens very precisely adjusted to work perfectly together. This is now even more important as digital picture quality is at the highest level for such a "small" camera. Maybe calibration tools used during production to adjust the M8 rangefinder are the same than the one used to assemble film leica M cameras. But digital capture made the proof that tolerances are now much more severe. Link to post Share on other sites More sharing options...
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