The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-50mm F2.8 DC DN C and the Leica SL 24-90mm F2.8-4 ASPH for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Leica SL 24-90mm F2.8-4 ASPH is the longer of the two lenses at 138mm. The Sigma 18-50mm F2.8 DC DN C with a length of 75mm is 63mm shorter. Besides being longer, the Leica SL 24-90mm F2.8-4 ASPH also has a larger diameter of 88mm compared to Sigma 18-50mm F2.8 DC DN C's 65mm 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 18-50mm F2.8 DC DN C weighs 290g, which means it is 850g (74%) lighter than the Leica SL 24-90mm F2.8-4 ASPH which has a weight of 1140g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Leica L Mount for size comparison purposes.
Standard Zoom Lenses in Leica L Mount for Size Comparison
Both Sigma 18-50mm F2.8 DC DN C and Leica SL 24-90mm F2.8-4 ASPH has the same Leica L lens mount. Some of the latest released cameras that are compatible with the Leica L lenses are Leica TL2, Leica TL and Leica T Typ 701.
Sigma 18-50mm F2.8 DC DN C is also available in Sony E and Fujifilm X mounts.
Sigma 18-50mm F2.8 DC DN C has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera. Leica SL 24-90mm F2.8-4 ASPH has a focal range of 24-90mm and 3.8X zoom ratio .