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 HD Pentax-FA 43mm F1.9 Ltd 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 HD Pentax-FA 43mm F1.9 Ltd 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 HD Pentax-FA 43mm F1.9 Ltd's 64mm diameter.
Below you can find a scaled side-by-side image of HD Pentax-FA 31mm F1.8 Ltd and HD Pentax-FA 43mm F1.9 Ltd to get a better idea of how their sizes compare in real life.
Comparison image of the HD Pentax-FA 31mm F1.8 Ltd and the HD Pentax-FA 43mm F1.9 Ltd Size and Weight 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. HD Pentax-FA 43mm F1.9 Ltd 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 HD Pentax-FA 43mm F1.9 Ltd 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 HD Pentax-FA 43mm F1.9 Ltd:
Lens Mounts
Both the HD Pentax-FA 31mm F1.8 Ltd and the HD Pentax-FA 43mm F1.9 Ltd 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 HD Pentax-FA 43mm F1.9 Ltd 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 .
