The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Voigtlander 20mm F3.5 SL II and the Pentax 14mm F2.8 ED for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Pentax 14mm F2.8 ED is the longer of the two lenses at 69mm. The Voigtlander 20mm F3.5 SL II with a length of 29mm is 40mm shorter. Besides being longer, the Pentax 14mm F2.8 ED also has a larger diameter of 84mm compared to Voigtlander 20mm F3.5 SL II's 63mm 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. Voigtlander 20mm F3.5 SL II weighs 205g, which means it is 215g (51%) lighter than the Pentax 14mm F2.8 ED which has a weight of 420g.
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
Lens Mounts
Both Voigtlander 20mm F3.5 SL II and Pentax 14mm F2.8 ED 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 K-1 II.
Voigtlander 20mm F3.5 SL II is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Voigtlander 20mm F3.5 SL II is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 30mm.
Pentax 14mm F2.8 ED is a prime lens with fixed focal lenght of 14mm which has an effective (full-frame 35mm equivalent) focal range of 21mm when used on a APS-C / DX format camera.