Telephoto is commonly referred to telephoto lenses (or tele), for SLRs and some
point and shoot cameras. Telephoto lenses on SLRs could range from the mild 100mm to strong 600mm, or even 800-1600mm, with a teleconverter. Tele lenses tend to be very
large, depending on how
fast they are and thier focal length. Canon's L-series "white lenses" seen at sporting events are commonly f/2.8 for 400mm, or f/4 for 600mm (there are tons of focal lengths and apertures in between). Common optical problems that plague most teles are vignetting,
barrel distortion, Pincushion distortion, and chromatic aberration (also known as purple fringing). Most telephoto lenses, and all
fast ones, are very expensive. There are cheap ones out there, like the Nikkor 70-
300 f/4-5.6G (which you could easily get for about $170). But if you want a pro quality paparazzi/sports style lens like Canon's 600mm f/4L IS USM, you'll have to invest a
little under $9000.
