The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 45mm F2.8 DG DN C and the Leica APO-SL 75mm F2 ASPH 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. Leica APO-SL 75mm F2 ASPH is the longer of the two lenses at 102mm. The Sigma 45mm F2.8 DG DN C with a length of 46mm, is 56mm shorter. Besides being longer, the Leica APO-SL 75mm F2 ASPH also has a larger diameter of 73mm compared to the Sigma 45mm F2.8 DG DN C's 64mm 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 45mm F2.8 DG DN C weighs 215g, which means it is 505g (70%) lighter than the Leica APO-SL 75mm F2 ASPH which has a weight of 720g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Leica L Mount for size comparison purposes.
Standard Lenses in Leica L Mount for Size Comparison
Filter Threads
The Sigma 45mm F2.8 DG DN C has a filter size of 55mm whereas the Leica APO-SL 75mm F2 ASPH has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sigma 45mm F2.8 DG DN C:
And these are the 67mm filters that we recommend for the Leica APO-SL 75mm F2 ASPH:
Lens Mounts
Both the Sigma 45mm F2.8 DG DN C and the Leica APO-SL 75mm F2 ASPH has the same Leica L lens mount. Some of the latest released cameras that are compatible with the Leica L lenses are Leica SL3, Panasonic S5 II and Panasonic S5 II X.
Sigma 45mm F2.8 DG DN C is also available in Sony E mount.
Focal Range
Sigma 45mm F2.8 DG DN C is a prime lens with fixed focal lenght of 45mm.
On the other hand, the Leica APO-SL 75mm F2 ASPH is a prime lens with fixed focal lenght of 75mm.