Originally posted by LaurenOE I noticed that the shutter speed went from 1/2000 down to 1/1000 at the end of the sequence, so the camera was "thinking" as it took the images.
It could have locked on the fence, but did not.
Lauren this is exactly the reason I've been interested in the K3 over my K5iis. Despite claims that the K3 AF is equal to the K5ii series in performance, I can easily replicate AF "failures" with such things as chain link fences, highly side/backlit grass (just the type you find in dawn or dusk shoots!) where PDAF prefers the fence or grass to a muted furry animal. I've even run into issues with white birds such as egrets amongst reeds, the camera likes the reeds better.
I'm using a sigma 100-300 f4 so its pretty easy to tell what the camera locked. I find it interesting that as I've gotten much better at tracking, I've found the critical limitations of my camera. If the K3 has solved these limitations, it'll be tough not to upgrade.
Even in slower tracking situations at a wildlife park that I encountered this weekend, my k5iis still preferred the chain link fence to the animal, In one situation, where the lioness was about 5 feet in front of a black, side lit chain link fence, if anything more than about 1/4 of the viewfinder contained fence, I could not get the camera to lock on the animal, this was using f4.5-5.6, center point focusing and no matter where the fence was in the composition.
Granted there are no chain link fences in Yellowstone, or most national parks, but the fact I can easily replicate a focus miss, and have had focus misses at critical times even without a chain link fence around, it starts to erode your confidence in the camera. Add to the fact I'm not using a Pentax lens and therefore can't use selective point AF, these kind of intelligence tests of the K3 AF are very welcome, except by my wallet.