The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-FA 31mm F1.8 Ltd and the Pentax FA 43mm F1.9 L 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. HD Pentax-FA 31mm F1.8 Ltd is the longer of the two lenses at 69mm. The Pentax FA 43mm F1.9 L with a length of 27mm, is 42mm shorter. Besides being longer, the HD Pentax-FA 31mm F1.8 Ltd also has a larger diameter of 65mm compared to the Pentax FA 43mm F1.9 L's 64mm 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 43mm F1.9 L weighs 155g, 54% (186g) lighter than the HD Pentax-FA 31mm F1.8 Ltd's weight of 341g.
Filter Threads
The HD Pentax-FA 31mm F1.8 Ltd has a filter size of 58mm whereas the Pentax FA 43mm F1.9 L has a 49mm 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 HD Pentax-FA 31mm F1.8 Ltd:
And these are the 49mm filters that we recommend for the Pentax FA 43mm F1.9 L:
Lens Mounts
Both the HD Pentax-FA 31mm F1.8 Ltd and the Pentax FA 43mm F1.9 L 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
HD Pentax-FA 31mm F1.8 Ltd 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 FA 43mm F1.9 L is a prime lens with fixed focal lenght of 43mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 64.5mm.
