Canon EF 200mm f/2.8L II USM

The Canon EF 200mm F2.8L II USM is a high-quality telephoto prime lens, compatible with Canon's full-frame and APS-C DSLRs. It's a great choice for enthusiasts, proving excellent image quality in a relatively lightweight, portable package. There are two main limitations though - this lens does not feature image stabilization, and although build-quality is up to normal Canon L-series standards, you don't get the same weather-sealing that is built into most newer L lenses. If you have the cash, Canon's EF 70-200mm F2.8L IS II USM is a better choice from the point of view of versatility, but the 200mm prime wins on cost and portability.