The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 24mm F2.8 STM and the Canon 28mm f2.8 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 28mm f2.8 IS USM is the longer of the two lenses at 52mm. The Canon 24mm F2.8 STM with a length of 23mm, is 29mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 68mm.
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 24mm F2.8 STM weighs 125g, which means it is 135g (51%) lighter than the Canon 28mm f2.8 IS USM which has a weight of 260g.
Filter Threads
The Canon 24mm F2.8 STM has a filter size of 52mm whereas the Canon 28mm f2.8 IS USM has a 58mm 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 24mm F2.8 STM:
And these are the 58mm filters that we recommend for the Canon 28mm f2.8 IS USM:
Lens Mounts
The Canon 24mm F2.8 STM has the Canon EF-S lens mount whereas the Canon 28mm f2.8 IS USM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount and Canon 1D X III, Canon 6D MII and Canon 5D MIV for the Canon EF Mount.
Focal Range
Canon 24mm F2.8 STM is a prime lens with fixed focal lenght of 24mm which has an effective (full-frame 35mm equivalent) focal range of
38.4mm when used on a APS-C / DX format camera.
On the other hand, the Canon 28mm f2.8 IS USM 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.