The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax FA 43mm F1.9 L and the Pentax D FA 645 55mm F2.8 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. Pentax D FA 645 55mm F2.8 is the longer of the two lenses at 68mm. The Pentax FA 43mm F1.9 L with a length of 27mm, is 41mm shorter. Besides being longer, the Pentax D FA 645 55mm F2.8 also has a larger diameter of 81mm 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, which means it is 261g (62%) lighter than the Pentax D FA 645 55mm F2.8 which has a weight of 416g.
Filter Threads
The Pentax FA 43mm F1.9 L has a filter size of 49mm whereas the Pentax D FA 645 55mm F2.8 has a 67mm 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 Pentax FA 43mm F1.9 L:
And these are the 67mm filters that we recommend for the Pentax D FA 645 55mm F2.8:
Lens Mounts
The Pentax FA 43mm F1.9 L has the Pentax KAF lens mount whereas the Pentax D FA 645 55mm F2.8 has the Pentax 645AF2 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 Pentax 645Z, Pentax 645D and for the Pentax 645AF2 Mount.
Focal Range
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.
On the other hand, the Pentax D FA 645 55mm F2.8 is a prime lens with fixed focal lenght of 55mm.
