I have what seems to be a wierd problem with my Canon 75-300, I'm using it with a D30 and purchased it only 5 months ago. It worked fine for 2 months but then started having difficulty focussing, it would focus pretty close to where it should be but just not quite in the right spot. What makes this a bit odd is that when I come home and focus on things through my window it works fine-could it be possible that it just doesn't want to focus on moving objects?
If I take it for a repair I know it will work fine when the repair guy gives it a try so I don't know what to do with it. In the meantime I have a 80-200 Canon lens that is okay for most stuff, but I really want my 75-300 to be something I can depend on.