Canon 300mm f/4 L IS USM review

The Canon 300mm f/4 L IS USM is an excellent pro lens that comes at a small price for this category. Note that this review reflects my opinion, based on my own experience. Though the Canon 300mm f/4 L IS USM is not considered a long lens, it is very versatile, with uses in bird photography, wildlife photography and sport photography. Coupled with a APS-C DSLR, like the Canon EOS 7D, the world of bird photography also opens up with a 480mm effective focal range.

Take a peak at where this lens falls in the Canon L series lens lineup:

Lens	Weight	Min. focus distance	Magnification	Dimensions w/o hood	Filter	Year
Canon 70-200mm f/2.8 L IS II	3.29 lbs (1.47kg)	3.94 ft (1.5m)	0.21x	3.4×7.8″ (86x197mm)	77mm	2010
Canon 100-400mm f/5.6 L IS	3.04 lbs (1.36kg)	5.9 ft (1.8m)	0.20x	3.6×7.4″ (92x189mm)	77mm	1998
Canon 300mm f/4 L IS	2.63 lbs (1.19kg)	3.94 ft (1.5m)	0.24x	3.5×8.7″ (90x221mm)	77mm	1997
Canon 300mm f/2.8 L IS II	5.19 lbs (2.35kg)	6.56 ft (2m)	0.18x	5.0×9.8″ (128x248mm)	52mm drop-in	2011
Canon 400mm f/5.6 L	2.76 lbs (1.25kg)	11.48 ft (3.5m)	0.12x	3.5×10.1″ (90x257mm)	77mm	1993

The Canon 300mm f/4 Image Stabilizer

The Canon 300mm f/4 L IS USM is equipped with the first generation Image Stabilizer, which gives a gain of 2 f-stops when handholding. 2 Image Stabilizer modes are available; the first one helps with both horizontal and vertical stabilization, while the second one helps with panning by automatically picking horizontal or vertical stabilization based on the panning direction. Note that the Image Stabilizer mechanism can be a bit noisy at times.

The Canon 300mm f/4 Construction

The Canon 300mm f/4 L IS USM’s optical construction is made of 15 elements in 11 groups. There are 2 Ultra-low Dispersion (UD) elements to help with aberrations correction. With 8 aperture blades, blurs are pleasing and the filter size is 77mm. For a lens of that focal range, it is fairly light with 42oz (1190g), which makes it a great flight lens for bird photography. Note that there a built-in hood that easily extends out and is quite practical. It is possible to add the 1.4x Extender III while maintaining autofocus, and the 2x Extender III in manual focus only for non EOS 1D bodies. Optical quality decreases a bit with extenders though.

Autofocus and sharpness

The Canon 300mm f/4 L IS USM focuses fast and accurately thanks to the Ultrasonic Motor (USM). Accuracy is very good for that price level, and it makes for a great light action lens. You can see in our sample images that birds in flight can come out very sharp! The Canon 300mm f/4 L IS USM does very well in Hummingbird photography for instance!

This lens is one of the sharpest lenses there is in that price range. Sharpness is very good at f/4, with a slight improvement at f/5.6. Color and contrast are very good, while blurs are pleasing thanks to the 8 blade aperture.

Macro Lens?

The Canon 300mm f/4 L IS USM can also be used as a macro lens! The high magnification of x0.24 combined with a fairly short minimum focus distance help making this lens a good substitute for macro photography. In fact, the x0.24 magnification is the highest you can get without picking out an actual macro lens. It does very nicely for flowers and big insects.

Which one to choose?

The Canon 300mm f/4 L IS USM competes mainly with the Canon 100-400mm f/5.6 L IS USM and the Canon 400mm f/5.6 L USM (no Image Stabilizer on this one!). While the Canon 100-400mm f/5.6 L IS USM is the most versatile, and the Canon 400mm f/5.6 L USM offers the longest focal range for the weight. The Canon 300mm f/4 L IS USM is the sharpest and the lightest of the three, with the fastest autofocus. Review below the MTF charts for each:

The top left is the Canon 300mm f/4 L IS USM MTF chart, the top right is the Canon 400mm f/5.6 L USM MTF chart and the bottom ones are the Canon 100-400mm f/5.6 L IS USM MTF charts at 100mm and 400mm. See our article on how to read MTF charts if this is completely foreign to you. The solid lines (both blue and black) reach closer to 100% for the Canon 300mm f/4 L IS USM, both with aperture wide open (black lines) and at f/8 (blue lines). The bokeh will be very slightly more pleasing with the Canon 400mm f/5.6 L USM as the dotted lines are slightly closer to the solid lines.

As a result, we see the Canon 300mm f/4 L IS USM as the best in class in this price range. Though one might think that the focal range is a tad short for bird photography, we accomplished great bird shots with it across the years.