The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Venus 25mm F2.8 2.5-5X Ultra Macro and the Samyang 20mm F1.8 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 20mm F1.8 is the longer of the two lenses at 88mm. The Venus 25mm F2.8 2.5-5X Ultra Macro with a length of 65mm, is 23mm shorter. Besides being longer, the Samyang 20mm F1.8 also has a larger diameter of 83mm compared to the Venus 25mm F2.8 2.5-5X Ultra Macro's 82mm 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 25mm F2.8 2.5-5X Ultra Macro weighs 400g, which means it is 97g (19%) lighter than the Samyang 20mm F1.8 which has a weight of 497g.
Lens Mounts
Both the Venus 25mm F2.8 2.5-5X Ultra Macro and the Samyang 20mm F1.8 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Venus 25mm F2.8 2.5-5X Ultra Macro is also available in Nikon F (DX) , Pentax KAF2 and Sony E mounts.
Samyang 20mm F1.8 is also available in Canon EF-M , Fujifilm X, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
Focal Range
Venus 25mm F2.8 2.5-5X Ultra Macro is a prime lens with fixed focal lenght of 25mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
40mm.
On the other hand, the Samyang 20mm F1.8 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 32mm.