I was mucking about in the back garden yesterday and found that my 18-250 entirely too often could not focus on, for example, a flower head. It was mid-afternoon with medium-grey clouds. Focus was almost impossible in the "shade" under a good-sized tree and only somewhat better in areas exposed directly to the sky. Sawed back and forth a few times and gave up - blinking away.
This is a good-sized garden with only a few trees, not a dense forest.
I've sometimes had that trouble in other outdoor situations with the lens, occasionally even in bright shade.
I was using A priority to keep the aperature as large as possible but it was generally 5.6 - 6.3.
I was assuming that it was the K10D but then I swapped the Tamrom for my new DA 55-300. Instant relief. At the same aperatures and focal length.
I've always assumed that AF speed was determined by both the camera and the lens but the ability to get focus at all is determined by the camera.
Any thoughts?? The 18-250 range is entirely too useful to give up and I don't see replacing the lens with one of the new versions if I'm considering a K-7. I'm certain I cannot afford both.
As always, thanks for your wisdom.