Overview

The Canon EF 300mm f/4L IS USM is a well-built, relatively lightweight telephoto lens (2.6 lb) with excellent sharpness wide open and good corner sharpness on full frame. Its first-generation IS provides about 2 stops of stabilization, though it can be noisy. Autofocus is fast and accurate via Ring USM, but some note it could be better for fast action. Weaknesses include a slippery finish on bean bags and a retractable hood that may draw attention. It suits sports, wildlife, and bird photographers seeking a portable, sharp prime at a reasonable used price.