Canon EF 300mm f/4 USM L IS - Full Format Review / Test
Lens Reviews - Canon EOS (Full Format)
Saturday, 16 April 2011 14:31

Review by Klaus Schroiff, published April 2011


The Canon EF 300mm f/4 USM L IS is a member of Canon's prestigious L-class (Luxury) series. It is, of course, far from being a cheap lens in absolute terms but still much more affordable than its f/2.8 cousin and as such a quite interesting option for those mortals interested in e.g. sports- or wildlife-photography. A couple of years ago we tested the lens on an APS-C DSLR but now that full format DSLRs are within reach of normal mortals it is worth having a look at the performance in its native format.

Typical for Canon L class lenses the mechanical quality is excellent thanks to an body of metal and a smoothly operating, rubberized focus ring. The lens features a detachable tripod mount for a better balance on tripods - certainly a good idea regarding the weight of the lens. There's also a pretty convenient build-in lens hood which can be locked in its out-most position.

The lens incorporates a first-generation Image Stabilizer (IS) with a claimed gain of 2 f-stops for hand-held photography. Based on the field usage with this lens we'd confirm this claim. Due to the weight of the lens it may even be a little more than that. Unlike the consumer variants the IS system has 2 modes - mode 1 for static shooting (horizontal + vertical stabilization) and mode 2 for panning (horizontal OR vertical stabilization - the panning direction is automatically detected). Unlike the 2nd generation IS used in later designs the variant of the 300mm f/4 L IS has no tripod detection so IS needs to be switched off here in order to avoid interference effects. On an unstable tripod or monopod the IS can remain active - it just has to detect some kind of motion.

The lens features a very fast ring-type USM AF drive (rear focusing) with full-time manual focusing in one-shot AF mode. The minimal focus distance is 1.5m resulting in a max. magnification of ~1:4 (~1:3 with the 1.4x converter) - this is far better than on the recently tested EF 400mm f/5.6 USM L.

Optical construction15 elements in 11 groups inc. 2x UD element
Number of aperture blades8 (non-circular)
min. focus distance1.5 m (max. magnification ratio ~1:4)
Dimensions90 x 221 mm
Weight1190 g
Filter size77 mm (non-rotating)
Hoodbuild-in lens hood - barrel-shaped
Other featuresCompatible to EF converters. Focus limiter. Tripod mount.