The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Venus 4mm F2.8 FMFT and the Samyang 12mm f2.0 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. Samyang 12mm f2.0 is the longer of the two lenses at 59mm. The Venus 4mm F2.8 FMFT with a length of 26mm, is 33mm shorter. Besides being longer, the Samyang 12mm f2.0 also has a larger diameter of 73mm compared to the Venus 4mm F2.8 FMFT'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. Venus 4mm F2.8 FMFT weighs 135g, which means it is 125g (48%) lighter than the Samyang 12mm f2.0 which has a weight of 260g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Ultra-Wideangle Lenses in Micro Four Thirds Mount for Size Comparison
Lens Mounts
Both the Venus 4mm F2.8 FMFT and the Samyang 12mm f2.0 has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are OM System OM-3 Astro, OM System OM-5 II and OM System OM-3.
Samyang 12mm f2.0 is also available in Canon EF-M , Fujifilm X, Sony E and Samsung NX mounts.
Focal Range
Venus 4mm F2.8 FMFT is a prime lens with fixed focal lenght of 4mm which has an effective (full-frame 35mm equivalent) focal range of
8mm when used on a FourThirds format camera.
On the other hand, the Samyang 12mm f2.0 is a prime lens with fixed focal lenght of 12mm which has an effective (full-frame 35mm equivalent) focal range of 18mm when used on a APS-C / DX format camera.
