The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 16-28 F2.8 and the Canon RF-S 7.8mm F4 STM Dual 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 16-28 F2.8 is the longer of the two lenses at 91mm. The Canon RF-S 7.8mm F4 STM Dual with a length of 42mm, is 49mm shorter. Besides being longer, the Canon RF 16-28 F2.8 also has a larger diameter of 77mm compared to the Canon RF-S 7.8mm F4 STM Dual'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-S 7.8mm F4 STM Dual weighs 131g, 70% (314g) lighter than the Canon RF 16-28 F2.8's weight of 445g.
Filter Threads
The Canon RF 16-28 F2.8 has a filter size of 67mm whereas the Canon RF-S 7.8mm F4 STM Dual 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 67mm filters that we recommend you to consider for the Canon RF 16-28 F2.8:
And these are the 58mm filters that we recommend for the Canon RF-S 7.8mm F4 STM Dual:
Lens Mounts
Both the Canon RF 16-28 F2.8 and the Canon RF-S 7.8mm F4 STM Dual has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R6 V, Canon R6 III and Canon C50.
Focal Range
Canon RF 16-28 F2.8 has a focal range of 16-28mm and
1.8X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
25.6 - 44.8mm.
On the other hand, the Canon RF-S 7.8mm F4 STM Dual is a prime lens with fixed focal lenght of 7.8mm which has an effective (full-frame 35mm equivalent) focal range of 12.8mm when used on a APS-C / DX format camera.
