The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica TL 35mm F1.4 ASPH and the Sigma 30mm F1.4 EX DC HSM 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. Leica TL 35mm F1.4 ASPH is the longer of the two lenses at 77mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 18mm shorter. On the other hand, the Sigma 30mm F1.4 EX DC HSM has a larger diameter of 77mm compared to the Leica TL 35mm F1.4 ASPH's 70mm 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. Leica TL 35mm F1.4 ASPH weighs 128g, which means it is 302g (70%) lighter than the Sigma 30mm F1.4 EX DC HSM which has a weight of 430g.
Lens Mounts
The Leica TL 35mm F1.4 ASPH has the Leica TL lens mount whereas the Sigma 30mm F1.4 EX DC HSM has the Sigma SA lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Leica TL Mount and Sigma SD1 Merrill, Sigma SD1 and for the Sigma SA Mount.
Sigma 30mm F1.4 EX DC HSM is also available in Canon EF-S , Nikon F (DX), Four Thirds, Pentax KAF and Sony Alpha mounts.
Focal Range
Leica TL 35mm F1.4 ASPH is a prime lens with fixed focal lenght of 35mm which has an effective (full-frame 35mm equivalent) focal range of 52.5mm when used on a APS-C / DX format camera. 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.