So I've got my hands on a 55-300mm lens which I've heard nothing but good about! Having used it for a little while now, I've a bit of an issue with it; until just under focal lengths of 200mm it performs absolutely beautifully and I couldn't really ask for much more. But beyond that, it's... really nasty, honestly. Neither auto focus nor manual focus is able to produce an image that isn't pretty horribly blurred. I've looked around and seen that people suggest trying taking pictures in bright light with a very fast shutter speeds and tried that, but no progress made at all. The lens just seems to immediately go out of focus at higher focal lengths and it's really frustrating me. I'm not the best photographer ever but I feel like I should be able to at least take a picture with this thing that isn't really blurry. Any advice? I assume I'm doing something wrong given how happy people are with these lenses but is it possible that mine is simply defective?