While both cameras may be a little long in the tooth (especially the Sony), they are now at a very attractive priceponit, and they both remain very capable cameras:   "Comparing The Auto Focus- For this article I went ahead and bought a Tamron 70-300mm LD 1:2 macro so that I could compare both cameras with the exact same lens for autofocus performance. I already have this fine lens for the A700. After verifying both lenses have the same exact amount of screw turns from close focus to infinity, I then performed the testing. My first impression right off the bat was the fact that the K7 cycled through the focus range much quicker than the A700 does. The improvement is about the same as the improvement the A700 was over the old veteran A100. Yes, that much quicker. However, there was much more testing to do than that so I headed on over to the lake to catch some birds in flight, and hopefully some other moving objects."   Link