Originally posted by Kobie V1.40 and no real issues with using AF.C (both single point and expanded points all the way to 25).
Tracks great if you have a lens that focuses quickly and locks on the subject.
If the lens isn't that great, then yes, the camera will actually give up trying to get the lens focused (I've used a few lenses that cause this issue).
I find this happens more on screw driven lenses vs lenses with their own focusing motor.
One lens I do have that is capable of some fantastic shots is the Sigma 170-500 APO, the only problem with that lens is that AF.C is practically unusable. The lens will hunt instead of lock and then it just gives up (goes from solid green confirmation of focus to flashing, to solid, to flashing, then it just keeps flashing and gives up on focusing).
I actually do my birding photography (BIF as well) using AF.S when I have that lens mounted.
Thanks! With the Pentax 16-85 I have the problem as well, that's is the most "clever" AF lens I have. But the other screw driven lenses I have are Pentax so is not really making me happy ....