The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 24mm f2.8 IS USM and the Canon 28mm f2.8 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 24mm f2.8 IS USM is the longer of the two lenses at 56mm. The Canon 28mm f2.8 with a length of 43mm, is 13mm shorter. Besides being longer, the Canon 24mm f2.8 IS USM also has a larger diameter of 68mm compared to the Canon 28mm f2.8's 67mm 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 28mm f2.8 weighs 185g, 33% (95g) lighter than the Canon 24mm f2.8 IS USM's weight of 280g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Canon EF Mount for size comparison purposes.
Wideangle Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Canon 24mm f2.8 IS USM has a filter size of 58mm whereas the Canon 28mm f2.8 has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Canon 24mm f2.8 IS USM:
And these are the 52mm filters that we recommend for the Canon 28mm f2.8:
Lens Mounts
Both the Canon 24mm f2.8 IS USM and the Canon 28mm f2.8 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
Canon 24mm f2.8 IS USM is a prime lens with fixed focal lenght of 24mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
38.4mm.
On the other hand, the Canon 28mm f2.8 is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 44.8mm.