The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 300mm f2.8L IS USM and the Canon 300mm f4.0L IS USM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Canon 300mm f2.8L IS USM is the longer of the two lenses at 252mm. The Canon 300mm f4.0L IS USM with a length of 221mm, is 31mm shorter. Besides being longer, the Canon 300mm f2.8L IS USM also has a larger diameter of 128mm compared to the Canon 300mm f4.0L IS USM's 90mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Canon 300mm f4.0L IS USM weighs 1190g, 53% (1360g) lighter than the Canon 300mm f2.8L IS USM's weight of 2550g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Canon EF Mount for size comparison purposes.
Telephoto Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Canon 300mm f2.8L IS USM has a filter size of 52mm whereas the Canon 300mm f4.0L IS USM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 52mm filters that we recommend you to consider for the Canon 300mm f2.8L IS USM:
And these are the 77mm filters that we recommend for the Canon 300mm f4.0L IS USM:
Lens Mounts
Both the Canon 300mm f2.8L IS USM and the Canon 300mm f4.0L IS USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Focal Range
Both lenses have the same focal range of
300mm but while Canon 300mm f2.8L IS USM has the fastest aperture of
F2.8, the Canon 300mm f4.0L IS USM's widest aperture value is
F4.0.