The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-FA 43mm F1.9 Ltd and the Sigma 45mm F2.8 DG DN C 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. Sigma 45mm F2.8 DG DN C is the longer of the two lenses at 46mm. The HD Pentax-FA 43mm F1.9 Ltd with a length of 27mm, is 19mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 64mm.
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, which means it is 60g (27%) lighter than the Sigma 45mm F2.8 DG DN C which has a weight of 215g.
Filter Threads
The HD Pentax-FA 43mm F1.9 Ltd has a filter size of 49mm whereas the Sigma 45mm F2.8 DG DN C 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 49mm filters that we recommend you to consider for the HD Pentax-FA 43mm F1.9 Ltd:
And these are the 55mm filters that we recommend for the Sigma 45mm F2.8 DG DN C:
Lens Mounts
The HD Pentax-FA 43mm F1.9 Ltd has the Pentax KAF lens mount whereas the Sigma 45mm F2.8 DG DN C has the Sony E 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 FX5, Sony A7R VI and Sony A7 V for the Sony E Mount.
Sigma 45mm F2.8 DG DN C is also available in Leica L mount.
Focal Range
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.
On the other hand, the Sigma 45mm F2.8 DG DN C is a prime lens with fixed focal lenght of 45mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 67.5mm.
