Hi, I came looking for a photo forum to help us out with a problem. We have a Nikon D60 and have been using zoom lenses with no problems- a 200mm and a 300mm. We just got a 500mm, specifically a Sigma 50-500mm 1:4-6.3 APO DG HSM D and were all excited about getting some eagle pictures before they head back north. The lens is NOT autofocus. More often than not, the camera would tick-tick-tick, but wouldn't actually take a picture. Sun came out so there was plenty of light. He tried every setting on the dial, but couldn't find one that would work. Any ideas what we're doing wrong?