The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax FA 50mm F1.4 Classic and the Voigtlander 40mm F2 SL II 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. Pentax FA 50mm F1.4 Classic is the longer of the two lenses at 37mm. The Voigtlander 40mm F2 SL II with a length of 25mm, is 12mm shorter. Besides being longer, the Pentax FA 50mm F1.4 Classic also has a larger diameter of 65mm compared to the Voigtlander 40mm F2 SL II'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. Voigtlander 40mm F2 SL II weighs 200g, 7% (16g) lighter than the Pentax FA 50mm F1.4 Classic's weight of 216g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Pentax KAF Mount for size comparison purposes.
Standard Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
The Pentax FA 50mm F1.4 Classic has a filter size of 49mm whereas the Voigtlander 40mm F2 SL II 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 49mm filters that we recommend you to consider for the Pentax FA 50mm F1.4 Classic:
And these are the 52mm filters that we recommend for the Voigtlander 40mm F2 SL II:
Lens Mounts
Both the Pentax FA 50mm F1.4 Classic and the Voigtlander 40mm F2 SL II has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Voigtlander 40mm F2 SL II is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Pentax FA 50mm F1.4 Classic is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
75mm.
On the other hand, the Voigtlander 40mm F2 SL II is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 60mm.
