Canon EF 300mm f/4 USM L - Review / Test Report
Lens Reviews - Canon EOS (APS-C)

Review by Klaus Schroiff, published November 2005

Special thanks to Michael Huonker for providing this lens!


The Canon EF 300mm f/4 USM L is the predecessor of the current 300mm f/4 IS version. During its time it was and still is a highly regarded lens and it remains a well sought-after lens on the used market. On APS-C DSLRs such as the EOS 350D (used for testing) its field of view is equivalent to 480mm on full frame cameras so the obvious applications are sports and wildlife photography.

Due to the lack of an IS correction group the optical design is totally different with significantly less lens elements - just 8 elements in 7 groups including 2 UD elements. The aperture mechanism features 8 aperture blades. The min. focus distance is a little disappointing at 2.5m with a max. object magnification of about 1:8. As to be expected from such a lens it not exactly small with a size of 90x213mm and a weight of 1165g. The filter size of 77mm is in-line with many other pro grade Canon lenses. The lens can accept all Canon EF tele-converters resulting in either a 420mm f/5.6 (300mm + 1.4x) or 600mm f/8 (300mm + EF 2x) combination. In the scope of this review we can take a closer look at its performance with the Canon EF 1.4x II (=420mm full frame or equivalent to 588mm on APS-C).

The mechanical quality of the lens is excellent with an outer barrel made of metal and a broad rubberized focus ring which is smooth and well damped. The focus range can be restricted to 6m-∞ and 2.5m-∞. The lens also features a detachable tripod mount for a better balance on tripods - certainly a good idea regarding the weight of the lens. ThereĀ“s also a pretty convenient build-in lens hood (see the middle product shot above). Unfortunately is cannot be locked in its outmost position so it tends to get retracted when touched unintentionally.