I'm looking to buy an inexpensive telephoto (for a Canon Rebel XT) for a little trip on Monday. I'm currently based in a remote Nevada town that has one (Ritz) camera shop. My options: the Canon EF 75-300mm $199, EF-S 55-250mm IS $250, and a Quantary (Salesman claims it's a re-branded Tamron) 70-300mm $150. My question: Are the two cheaper lenses worth buying at all? I've heard that the Canon 75-300 doesn't perform well past about 200mm, and I know nothing about the Quantary. I feel like the IS lens is a little more than I wanted to spend. But the cheaper Canon lens isn't cheap enough to justify not getting the EF-S lens. Which leaves the mystery Quantary. A quick google of camera forums does not give me positive reviews of Quantary lenses... I want to use the lens for photographing architectural details and details on industrial objects too far above the ground to get close to, and a little wildlife shooting. What's the verdict? is the EF-S lens worth spending the extra money on, or are all three lenses equally low-end?