The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 30mm F1.4 EX DC HSM and the Carl Zeiss Distagon T2,8/25 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Carl Zeiss Distagon T2,8/25 is the longer of the two lenses at 90mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 31mm shorter. On the other hand, the Sigma 30mm F1.4 EX DC HSM has a larger diameter of 77mm compared to the Carl Zeiss Distagon T2,8/25's 64mm diameter.
The 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 F1.4 EX DC HSM weighs 430g, which means it is 50g (10%) lighter than the Carl Zeiss Distagon T2,8/25 which has a weight of 480g.
Lens Mounts
Both the Sigma 30mm F1.4 EX DC HSM and the Carl Zeiss Distagon T2,8/25 has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax KF, Pentax K-3 III and Pentax KP.
Sigma 30mm F1.4 EX DC HSM is also available in Canon EF-S , Nikon F (DX), Four Thirds, Sony Alpha and Sigma SA mounts.
Carl Zeiss Distagon T2,8/25 is also available in Nikon F (FX) mount.
Focal Range
Sigma 30mm F1.4 EX DC HSM 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. Carl Zeiss Distagon T2,8/25 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.