MT Shooter wrote:
Design tolerances can vary between lenses, even of the exact same model. While these variances are minimal, the lens to sensor distance is so critical that if a lens is at one end or the other or the acceptable tolerance window, you may not be totally happy with the sharpness of the resulting image. Better quality camera bodies all allow for the end user to "Tune" the AF point of that camera to the particular lens in use.
Its actually a very simple operation once you learn how to do it, and each photographer whose camera has that capability definitely should take the time to at least TEST each lenses AF accuracy so he or she KNOWS what that lens is focusing on. Adjustments can be, and usually are, quite minimal, but can make a very noticeable difference in image sharpness and overall quality.
Design tolerances can vary between lenses, even of... (
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In addition as you use your camera and swap lenses sooner or later the wear on the mount can affect focus settings, as can silly things like temperature changes. Not to any great magnitude but over time the various things that can alter the original setting can add up and may require you to re-tune your focus settings.