The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 24-70mm f4L IS USM and the Canon 24-70mm f2.8L USM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Canon 24-70mm f2.8L USM is the longer of the two lenses at 124mm. The Canon 24-70mm f4L IS USM with a length of 93mm is 31mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 83mm.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Canon 24-70mm f4L IS USM weighs 600g, which means it is 350g (36%) lighter than the Canon 24-70mm f2.8L USM which has a weight of 950g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Canon EF Mount for size comparison purposes.
Standard Zoom Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both Canon 24-70mm f4L IS USM and Canon 24-70mm f2.8L 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 24-70mm but while Canon 24-70mm f4L IS USM has the fastest aperture of F4.0, the Canon 24-70mm f2.8L USM's widest aperture value is F2.8.