I have a Canon 1000d, and the standard lens EF-S 18-55mm. Recently I was out taking photos and I've noticed that if I zoom in fully, the lens can't auto focus. I can still take shots using manual focus at full zoom though.
It will just try and find focus constantly buzzing back and forth for as long as I hold the shutter. I was in a bird hide and was holding the shutter and moving the camera around and it was doing it constantly until I pointed it at something nearby.
Does anyone have any idea on why this might be happening? I'm really worried that I've damaged the lens in some way. Or does my kit just need cleaning?
Any advice would be great. My camera lives in a camera bag when not in use, so I don't think it could be dust. I also have a clear filter to protect the shooting end of the lens.