The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF-S 7.8mm F4 STM Dual and the Venus Laowa 4mm F2.8 RF 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 7.8mm F4 STM Dual is the longer of the two lenses at 42mm. The Venus Laowa 4mm F2.8 RF with a length of 26mm, is 16mm shorter. Besides being longer, the Canon RF-S 7.8mm F4 STM Dual also has a larger diameter of 69mm compared to the Venus Laowa 4mm F2.8 RF's 61mm 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, which means it is 4g (2%) lighter than the Venus Laowa 4mm F2.8 RF which has a weight of 135g.
Below you can find the dimension and weight table of the Dual Wideangle Prime Lenses in Canon RF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Canon RF Mount for Size Comparison
Lens Mounts
Both the Canon RF-S 7.8mm F4 STM Dual and the Venus Laowa 4mm F2.8 RF 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 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.
On the other hand, the Venus Laowa 4mm F2.8 RF is a prime lens with fixed focal lenght of 4mm which has an effective (full-frame 35mm equivalent) focal range of 6mm when used on a APS-C / DX format camera.
