The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 30mm F2.8 DN and the Venus 25mm F2.8 2.5-5X Ultra Macro 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 25mm F2.8 2.5-5X Ultra Macro is the longer of the two lenses at 65mm. The Sigma 30mm F2.8 DN with a length of 41mm, is 24mm shorter. Besides being longer, the Venus 25mm F2.8 2.5-5X Ultra Macro also has a larger diameter of 82mm compared to the Sigma 30mm F2.8 DN'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. Sigma 30mm F2.8 DN weighs 135g, which means it is 265g (66%) lighter than the Venus 25mm F2.8 2.5-5X Ultra Macro which has a weight of 400g.
Lens Mounts
Both the Sigma 30mm F2.8 DN and the Venus 25mm F2.8 2.5-5X Ultra Macro has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A6700, Sony FX30 and Sony ZV-E10.
Sigma 30mm F2.8 DN is also available in Micro Four Thirds mount.
Venus 25mm F2.8 2.5-5X Ultra Macro is also available in Canon EF , Nikon F (DX) and Pentax KAF2 mounts.
Focal Range
Sigma 30mm F2.8 DN is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of
45mm when used on a APS-C / DX format camera.
On the other hand, the 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 1.5x crop, it provides a 35mm (FF) equivalent of 37.5mm.