MLFLY

I would suggest you try an object at a medium range at a couple of varied zoom and aperture settings from a tripod. That's the only way to tell if the lens is sharp. Photograph something that allows you to judge sharpness - say, a fence or similar. If that softness remains, I wouldn't be happy and would exchange it with another one. I had to send back a 55-200 and I'm very happy with the second one.