If there are already other threads addressing my questions, please feel free to point me to 'em.

I would have bet this subject was already covered ad nauseum but I can't seem to find what I'm looking for with the search engine, so . . .

I'd like to know about your experience with calibrating bodies to lens(es).

I'm using the LCD moire method described at various sites on the Web in conjunction with Live View.

I've read that the recommended test distance is at least 50x the focal length of the lens being tested. But when I called Canon U.S., the 'tech' told me to test at the distance at which the lens is most likely to be used. He downplayed the 50x approach.

His suggestion makes more sense to me, i.e., optimize for a commonly used distance. Of course that will vary, but I tend to work relatively close to my subjects so testing a 200mm lens at 10+ meters doesn't make a lot of sense to me. Unless, of course, it works better.

The other question is about zooms. I've read that it's best to test at the longest focal length; have you found that to be true? Almost all AF zoom designs are actually varifocal rather than true zooms so every change of zoom requires refocusing.

TIA and apologies if this has already been beaten to death.

ScottGee1