Hey all. I've been very curious lately about the difference in focus speed between two camera models with the same lens. I've found a video (hopefully posting this is legal) that pretty much proves that there is a HUGE difference in focusing speed for a lens using different camera models. I've been eyeing different 70-200mm 2.8 zooms for the K-x and was going between the FA 80-200 and the tamron 70-200 2.8 macro. I was hesitant about the tamron because of the widespread complaints about focus speed (and sticking aperture) and hesitant about the FA because of, well, yeah ($). I went for the tamron. As long as it holds up for a while, with no aperture sticking issues, etc., I can't go wrong, considering the optics. But as far as focusing speed, people don't seem to relate that much to the body they're using. Judging from this test, it should be a big, big factor and not just the lens gearing. In the posted video, the pitch of the K-7's motor "whir" is much higher than the K100's (indicating zippier focus), and the difference in the speed of the focus travel is also pretty simple evidence. The K-x is somewhere in between, but has significantly faster focus motor speed than the K100. Good info. to have.
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