08-30-2010, 07:42 AM
All are extremly good lenses. VEry sharp etc. You should try them all and see for yourself whether you need the extended focal length or the brighter aperture. There is really no better advice I can give you. It maybe good to go for more FL if you dont have or intend to buy a tele zoom. for travel it is also more convenient not to have to change lenses all the time. But then, a larger aperture is better for isolating subjects from the background and for low light action. You decide. When I was shooting aps-c I had both, a Canon 17-85 and a tamron 17-50 f/2.8. Horses for causes.