This is a compromise lens. It’s not quite as sharp as the 300 and 400mm primes and has a telescoping zoom which some people don’t like. Personally, I appreciate this feature since it’s faster to zoom. The Canon 70-200 f/2.8L IS II is sharper than this lens from 100-200mm. Trip after trip, however, I pack up 2 or 3 “best possible” lenses only to unpack them and put a 100-400mm in my bag. This is because, although it’s a compromise, it’s a very good compromise. It’s nearly as sharp as the primes and far sharper than a consumer lens. The huge range means getting the shot framed just right and not having to change lenses, and it’s relatively small and easy to shoot hand-held.
March 2013