The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Venus 8-15mm 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. Venus 8-15mm f2.8 is the longer of the two lenses at 76mm. The Canon RF-S 7.8mm F4 STM Dual with a length of 42mm, is 34mm shorter. Besides being longer, the Venus 8-15mm f2.8 also has a larger diameter of 95mm 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, 79% (519g) lighter than the Venus 8-15mm f2.8's weight of 650g.
Lens Mounts
Both the Venus 8-15mm 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.
Venus 8-15mm f2.8 is also available in the Sony E , Nikon Z and Leica L mounts.
Focal Range
Venus 8-15mm f2.8 has a focal range of 8-15mm and
1.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
12.8 - 24mm.
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.