Re: Question about Lenses

FWIW, I use an 18-200 (Nikon) and have been more than happy with it. It seems to be a very popular lens among the railfan photogs I meet. Reasonably sharp, flexible and lightweight. Not cheap, but in general you get what you pay for. At the tele end it is close to tack sharp, at the wide angle end there is some softness when wide open, but overall pretty good. Not only is not having to change lenses convenient, but it also minimizes the opportunity for dust to get on your sensor. I have found that I focus more on the image and less on the gear. I suspect that Canon has a similar lens. With today's vibration reduction technology, I rarely use a tripod even for tele shots, and when I do it is more for framing precision than vibration reduction. If you want tack sharp shots at every focal length and aperture, use high quality fixed focal length lenses, but the additional sharpness you get is going to be helpful primarily (perhaps only) if you do large prints.

JBWX