The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 20mm f2.8 USM and the Canon 24-105mm F4L IS II 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 24-105mm F4L IS II is the longer of the two lenses at 118mm. The Canon 20mm f2.8 USM with a length of 71mm, is 47mm shorter. Besides being longer, the Canon 24-105mm F4L IS II also has a larger diameter of 84mm compared to the Canon 20mm f2.8 USM's 78mm 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 20mm f2.8 USM weighs 405g, which means it is 390g (49%) lighter than the Canon 24-105mm F4L IS II which has a weight of 795g.
Filter Threads
The Canon 20mm f2.8 USM has a filter size of 72mm whereas the Canon 24-105mm F4L IS II 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 72mm filters that we recommend you to consider for the Canon 20mm f2.8 USM:
And these are the 77mm filters that we recommend for the Canon 24-105mm F4L IS II:
Lens Mounts
Both the Canon 20mm f2.8 USM and the Canon 24-105mm F4L IS II 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 20mm f2.8 USM is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
32mm.
On the other hand, the Canon 24-105mm F4L IS II has a focal range of 24-105mm and 4.4X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 38.4 - 168mm.