The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 21mm F3.2 AL L and the Carl Zeiss Distagon T2/28 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. Carl Zeiss Distagon T2/28 is the longer of the two lenses at 93mm. The Pentax 21mm F3.2 AL L with a length of 25mm, is 68mm shorter. Besides being longer, the Carl Zeiss Distagon T2/28 also has a larger diameter of 64mm compared to the Pentax 21mm F3.2 AL L's 63mm 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. Pentax 21mm F3.2 AL L weighs 140g, which means it is 380g (73%) lighter than the Carl Zeiss Distagon T2/28 which has a weight of 520g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Pentax KAF Mount for size comparison purposes.
Wideangle Prime Lenses in Pentax KAF Mount for Size Comparison
Both the Pentax 21mm F3.2 AL L and the Carl Zeiss Distagon T2/28 has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax KF, Pentax K-3 III and Pentax KP.
Pentax 21mm F3.2 AL L is also available in Pentax KAF mount.
Carl Zeiss Distagon T2/28 is also available in Canon EF and Nikon F (FX) mounts.
Pentax 21mm F3.2 AL L is a prime lens with fixed focal lenght of 21mm which has an effective (full-frame 35mm equivalent) focal range of 31.5mm when used on a APS-C / DX format camera. Carl Zeiss Distagon T2/28 is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 42mm.