The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Venus 12mm f2.8 MF and the Tamron 20mm F2.8 Di III OSD M1:2 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 12mm f2.8 MF is the longer of the two lenses at 78mm. The Tamron 20mm F2.8 Di III OSD M1:2 with a length of 64mm, is 14mm shorter. Besides being longer, the Venus 12mm f2.8 MF also has a larger diameter of 77mm compared to the Tamron 20mm F2.8 Di III OSD M1:2's 73mm 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. Tamron 20mm F2.8 Di III OSD M1:2 weighs 220g, 41% (157g) lighter than the Venus 12mm f2.8 MF's weight of 377g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony E Mount for Size Comparison
Filter Threads
The Venus 12mm f2.8 MF has a filter size of 72mm whereas the Tamron 20mm F2.8 Di III OSD M1:2 has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Venus 12mm f2.8 MF:
And these are the 67mm filters that we recommend for the Tamron 20mm F2.8 Di III OSD M1:2:
Lens Mounts
Both the Venus 12mm f2.8 MF and the Tamron 20mm F2.8 Di III OSD M1:2 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX5, Sony A7R VI and Sony A7 V.
Venus 12mm f2.8 MF is also available in the Nikon Z , Canon RF and Leica L mounts.
Focal Range
Venus 12mm f2.8 MF is a prime lens with fixed focal lenght of 12mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
18mm.
On the other hand, the Tamron 20mm F2.8 Di III OSD M1:2 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 30mm.