The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-FA 35mm F2 AL and the Pentax 40mm F2.8 XS Lens 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 35mm F2 AL is the longer of the two lenses at 45mm. The Pentax 40mm F2.8 XS Lens with a length of 9mm, is 36mm shorter. Besides being longer, the HD Pentax-FA 35mm F2 AL also has a larger diameter of 64mm compared to the Pentax 40mm F2.8 XS Lens's 63mm 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 40mm F2.8 XS Lens weighs 45g, 76% (148g) lighter than the HD Pentax-FA 35mm F2 AL's weight of 193g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Pentax KAF Mount for size comparison purposes.
Standard Lenses in Pentax KAF Mount for Size Comparison
Lens Mounts
Both the HD Pentax-FA 35mm F2 AL and the Pentax 40mm F2.8 XS Lens 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 35mm F2 AL is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
52.5mm.
On the other hand, the Pentax 40mm F2.8 XS Lens is a prime lens with fixed focal lenght of 40mm which has an effective (full-frame 35mm equivalent) focal range of 60mm when used on a APS-C / DX format camera.
