Quote:
Originally Posted by glenerrolrd
Rob/Mark They are taking care of the lenses and that is not an issue . I expect that the M8 and future versions will be my primary system....and I am convinced that periodic calibration will be required (if for no other reason than my lenses will change). My interest is in better understanding how the collimation test fits in (is it really telling us anything different from the "star test" using the body ). The difference would appear to be that on the M8 testing always has some "maybe small" variance due to the range finder. The second question is surely at somepoint subjective....Marks analysis would indicate that if you have acceptable results at 200 yards then infinity should be acceptable (if not perfect). At the shorter distances ..I do as quick test on a wall chart....if the lens backfocuses(wide open) by more than 6 inches at 2M , I know it will show up in my images. The infinity test, other than being an important baseline, is more difficult for me to evaluate (how it impacts image quality). . Now a casual reader may ask.....who cares? But if you follow sean reid s testing of the rangefinder lenses..you can see that his testing methodology includes taking multiple images and picking the best This is to avoid the small focusing errors made by the user. These errors may be large enough to make the differences in sharpness(between your lens choices) irrelevant in practical photography. So you could argue that having a calibrated system is as important as buying the best glass. Since almost every lens in the M system is pretty darn good.
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Roger, the purpose of my analysis was to show you that what you seeing as significant issues are down to tiny adjustments. Even if the lens is reset to work on a particular body, the rangefinder can and does go out of alignment which renders any lens fine tuning, if not pointless, then at least compromised.
Sean focus brackets to obtain the best image the lens is capable of providing and in doing so, takes the rangefinder out as well as human error (such as it might exist) out of the equation. Add the rangefinder back in and any focussing error it introduces will affect image quality.
My own view is that the optical quality of Leica M lenses exceeds the ability of the Leica M rangefinder to focus them accurately, which is why I have proposed a scheme of user lens fine-tuning.
Nikon have recently added a fine tuning focus menu to the D3. I have found this is mainly useful for dialling in a degree of front focus when the lens is focussed wide-open so that focus shift back as the lens is stopped down remains within the depth of field. I mainly use it with the fastest glass, for example, the 85mm f1.4.