The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF-S 3.9mm F3.5 and the Canon RF 10-20mm F4 L IS STM 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 RF 10-20mm F4 L IS STM is the longer of the two lenses at 112mm. The Canon RF-S 3.9mm F3.5 with a length of 55mm, is 57mm shorter. On the other hand, the Canon RF-S 3.9mm F3.5 has a larger diameter of 112mm compared to the Canon RF 10-20mm F4 L IS STM's 84mm 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 RF-S 3.9mm F3.5 weighs 290g, which means it is 280g (49%) lighter than the Canon RF 10-20mm F4 L IS STM which has a weight of 570g.
Lens Mounts
Both the Canon RF-S 3.9mm F3.5 and the Canon RF 10-20mm F4 L IS STM has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R50 V, Canon R100 and Canon R50.
Focal Range
Canon RF-S 3.9mm F3.5 is a prime lens with fixed focal lenght of 3.9mm which has an effective (full-frame 35mm equivalent) focal range of
6.4mm when used on a APS-C / DX format camera.
On the other hand, the Canon RF 10-20mm F4 L IS STM has a focal range of 10-20mm and 2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 15 - 30mm.
