The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Voigtlander Nokton 25mm F0.95 and the Sigma 30mm F2.8 EX DN for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Voigtlander Nokton 25mm F0.95 is the longer of the two lenses at 70mm. The Sigma 30mm F2.8 EX DN with a length of 39mm is 31mm shorter. On the other hand, the Sigma 30mm F2.8 EX DN has a larger diameter of 61mm compared to Voigtlander Nokton 25mm F0.95's 58mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Sigma 30mm F2.8 EX DN weighs 135g, 67% (275g) lighter than the Voigtlander Nokton 25mm F0.95's weight of 410g.
Lens Mounts
Both Voigtlander Nokton 25mm F0.95 and Sigma 30mm F2.8 EX DN 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-5, Panasonic GH6 and OM System OM-1.
Sigma 30mm F2.8 EX DN is also available in Sony E mount.
Focal Range
Voigtlander Nokton 25mm F0.95 is a prime lens with fixed focal lenght of 25mm which has a 35mm equivalent focal range of 50mm when used on a FourThirds format camera. Sigma 30mm F2.8 EX DN is a prime lens with fixed focal lenght of 30mm which has a 35mm equivalent focal range of 37.5mm when used on a APS-C / DX format camera.