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 16mm F2.8 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-S 3.9mm F3.5 is the longer of the two lenses at 55mm. The Canon RF 16mm F2.8 STM with a length of 40mm, is 15mm shorter. Besides being longer, the Canon RF-S 3.9mm F3.5 also has a larger diameter of 112mm compared to the Canon RF 16mm F2.8 STM's 69mm 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 16mm F2.8 STM weighs 165g, 43% (125g) lighter than the Canon RF-S 3.9mm F3.5's weight of 290g.
Filter Threads
The Canon RF-S 3.9mm F3.5 has a filter size of 31mm whereas the Canon RF 16mm F2.8 STM has a 43mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 31mm filters that we recommend you to consider for the Canon RF-S 3.9mm F3.5:
And these are the 43mm filters that we recommend for the Canon RF 16mm F2.8 STM:
Lens Mounts
Both the Canon RF-S 3.9mm F3.5 and the Canon RF 16mm F2.8 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 16mm F2.8 STM is a prime lens with fixed focal lenght of 16mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 25.6mm.
