
Originally Posted by
ericbowles
I've got a D300 and 300 f/4 lens. The 300 f/4 lens does have some minor issues with AF if the subject is extremely out of focus. Sometimes there is hunting but it seems that the more frequent result is to simply do nothing - the camera refuses to focus until you give it some "help" with manual focus adjustment or by refocusing on something else close to the same plane. This is something that happens infrequently - and not just in low light. For what it's worth, my 600 f/4 has the same issue.
If I understand the issue you are having, this is an occasional problem. My suggestion is to learn how your lens and camera perform best and adapt your use as needed.