I have a second-hand 28-70mm zoom. I'm wondering if it's really not as sharp as I thought. I can't quite tell if I'm just not focusing too crisply or what. My canon SLR focuses and meters at "wide open" so maybe it's something that kicks in when the iris closes or maybe I'm just imagining it. Granted I've only had the lens for a few rolls of film now, but either I'm flubbing the focus (a real possibility) or it's coming out a tad blurred. Is what you see what you get with regards to sharpness? Seems pretty sharp, crisp, and in-focus in my viewfinder. When I get the print back it lacks a bit. Just a tad soft. What's the best way to test sharpness? I suppose I could compare similar zoom levels with my prime lenses? I could compare 28mm, 50mm, and the 80mm on my telephoto with the 70mm on this one, but that takes a lot of time and effort. I'm not sorry I got the lens. It's quite a time-saver. If it's a little soft I will live with it. I paid a lower price for it than I would have if it were new. It's more than paid for itself. It would be good to know, though, if I'm going to take a nice photo such as a landscape or a portrait that this might be the second choice to reach for in my bag.