The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax FA 31mm F1.8 L and the Pentax 14mm F2.8 ED for their suitability to various photography scenarios:
Size and Weight Comparison
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. Pentax FA 31mm F1.8 L weighs 345g, which means it is 75g (17%) 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 Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
The Pentax FA 31mm F1.8 L has a filter size of 58mm whereas the Pentax 14mm F2.8 ED has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Pentax FA 31mm F1.8 L:
And these are the 77mm filters that we recommend for the Pentax 14mm F2.8 ED:
Lens Mounts
Both the Pentax FA 31mm F1.8 L and the 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 K-3 III Mono, Pentax KF and Pentax K-3 III.
Focal Range
Pentax FA 31mm F1.8 L is a prime lens with fixed focal lenght of 31mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
46.5mm.
On the other hand, the 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.
