The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica SL 21mm F2 ASPH and the Leica Summicron-T 23mm 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 SL 21mm F2 ASPH is the longer of the two lenses at 102mm. The Leica Summicron-T 23mm f2 ASPH with a length of 37mm, is 65mm shorter. Besides being longer, the Leica SL 21mm F2 ASPH also has a larger diameter of 73mm compared to the Leica Summicron-T 23mm f2 ASPH's 63mm 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. Leica Summicron-T 23mm f2 ASPH weighs 154g, 80% (635g) lighter than the Leica SL 21mm F2 ASPH's weight of 789g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Leica L Mount for size comparison purposes.
Wideangle Lenses in Leica L Mount for Size Comparison
Filter Threads
The Leica SL 21mm F2 ASPH has a filter size of 67mm whereas the Leica Summicron-T 23mm f2 ASPH has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Leica SL 21mm F2 ASPH:
And these are the 52mm filters that we recommend for the Leica Summicron-T 23mm f2 ASPH:
Lens Mounts
Both the Leica SL 21mm F2 ASPH and the Leica Summicron-T 23mm 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-P, Panasonic S1 II and Panasonic S1 IIE.
Focal Range
Leica SL 21mm F2 ASPH is a prime lens with fixed focal lenght of 21mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
31.5mm.
On the other hand, the Leica Summicron-T 23mm f2 ASPH is a prime lens with fixed focal lenght of 23mm which has an effective (full-frame 35mm equivalent) focal range of 34.5mm when used on a APS-C / DX format camera.
