Stmall
Member
Hi all, and thanks for any help you can give...
I use a d500 and 500pf for wildlife, mainly uk birds and bif. All hunky dory until today.
First shot today was as a kestrel flew close by. Fired off a few shots against a close dark low background, which were great. The bird then went up against a monochrome sky and the group focus refused to find it. Testing established that the group focus operates normally until it rests on a monochrome sky when the focus locks out. Drop the aim to something with contrast whilst holding bbf continuous focus and it remains locked out. Toggle the af-on button and it focused normally again.
Back home did some more tests. With single point all is normal. As soon as I change to group or d25 then the issue arises. Monochrome grey or blue sky just seems to cause the lens to focus 'beyond infinity' and lock until af-on released and pressed at a subject with contrast. Single point against monochrome hunts and stops but with af-on still pressed will focus normally if put to a subject with contrast. Thus in group/d25 when I lose a bird I just can't get it back.
With a different lens this issue doesn't seem to arise. More worryingly, with a 1.4TC attached to the 500pf all seems absolutely normal.
I have tried cleaning the contacts but no change there. Also a factory reset on the camera made no difference.
It seems like a lens problem but why would adding the TC resolve the issue?
Help please. Has anyone any suggestions as to cause and how to resolve.
Thanks in anticipation.
I use a d500 and 500pf for wildlife, mainly uk birds and bif. All hunky dory until today.
First shot today was as a kestrel flew close by. Fired off a few shots against a close dark low background, which were great. The bird then went up against a monochrome sky and the group focus refused to find it. Testing established that the group focus operates normally until it rests on a monochrome sky when the focus locks out. Drop the aim to something with contrast whilst holding bbf continuous focus and it remains locked out. Toggle the af-on button and it focused normally again.
Back home did some more tests. With single point all is normal. As soon as I change to group or d25 then the issue arises. Monochrome grey or blue sky just seems to cause the lens to focus 'beyond infinity' and lock until af-on released and pressed at a subject with contrast. Single point against monochrome hunts and stops but with af-on still pressed will focus normally if put to a subject with contrast. Thus in group/d25 when I lose a bird I just can't get it back.
With a different lens this issue doesn't seem to arise. More worryingly, with a 1.4TC attached to the 500pf all seems absolutely normal.
I have tried cleaning the contacts but no change there. Also a factory reset on the camera made no difference.
It seems like a lens problem but why would adding the TC resolve the issue?
Help please. Has anyone any suggestions as to cause and how to resolve.
Thanks in anticipation.
