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 Sony 35mm F1.4 G 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. Sony 35mm F1.4 G is the longer of the two lenses at 76mm. The Pentax FA 31mm F1.8 L with a length of 69mm, is 7mm shorter. Besides being longer, the Sony 35mm F1.4 G also has a larger diameter of 69mm compared to the Pentax FA 31mm F1.8 L's 65mm 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. Pentax FA 31mm F1.8 L weighs 345g, which means it is 165g (32%) lighter than the Sony 35mm F1.4 G which has a weight of 510g.
Filter Threads
The Pentax FA 31mm F1.8 L has a filter size of 58mm whereas the Sony 35mm F1.4 G has a 55mm 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 55mm filters that we recommend for the Sony 35mm F1.4 G:
Lens Mounts
The Pentax FA 31mm F1.8 L has the Pentax KAF lens mount whereas the Sony 35mm F1.4 G has the Sony Alpha lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount and Sony A99 II, Sony A68 and Sony A77 II for the Sony Alpha Mount.
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 Sony 35mm F1.4 G is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 52.5mm.
