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 40mm F1.4 DG HSM A 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. Sigma 40mm F1.4 DG HSM A is the longer of the two lenses at 131mm. The Leica TL 35mm F1.4 ASPH with a length of 77mm, is 54mm shorter. Besides being longer, the Sigma 40mm F1.4 DG HSM A also has a larger diameter of 88mm compared to the Leica TL 35mm F1.4 ASPH's 70mm 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.
Filter Threads
The Leica TL 35mm F1.4 ASPH has a filter size of 60mm whereas the Sigma 40mm F1.4 DG HSM A has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 60mm filters that we recommend you to consider for the Leica TL 35mm F1.4 ASPH:
And these are the 82mm filters that we recommend for the Sigma 40mm F1.4 DG HSM A:
Lens Mounts
The Leica TL 35mm F1.4 ASPH has the Leica TL lens mount whereas the Sigma 40mm F1.4 DG HSM A has the Sony E lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Leica TL Mount and Sony A9 III, Sony A7C Mark II and Sony A7CR for the Sony E Mount.
Sigma 40mm F1.4 DG HSM A is also available in Canon EF , Nikon F (FX), Sigma SA and Leica L 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.
On the other hand, the Sigma 40mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 60mm.