The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-D FA 50mm F1.4 SDM AW 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. HD Pentax-D FA 50mm F1.4 SDM AW is the longer of the two lenses at 106mm. The Pentax D FA 645 55mm F2.8 with a length of 68mm, is 38mm shorter. On the other hand, the Pentax D FA 645 55mm F2.8 has a larger diameter of 81mm compared to the HD Pentax-D FA 50mm F1.4 SDM AW's 80mm 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 D FA 645 55mm F2.8 weighs 416g, 54% (494g) lighter than the HD Pentax-D FA 50mm F1.4 SDM AW's weight of 910g.
Lens Mounts
The HD Pentax-D FA 50mm F1.4 SDM AW has the Pentax KAF3 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 KAF3 Mount and Pentax 645Z, Pentax 645D and for the Pentax 645AF2 Mount.
Focal Range
HD Pentax-D FA 50mm F1.4 SDM AW is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
75mm.
On the other hand, the Pentax D FA 645 55mm F2.8 is a prime lens with fixed focal lenght of 55mm.
