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 70mm F2.4 AL L 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 70mm F2.4 AL L with a length of 26mm, is 19mm shorter. Besides being longer, the HD Pentax-FA 35mm F2 AL also has a larger diameter of 64mm compared to the Pentax 70mm F2.4 AL L'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 70mm F2.4 AL L weighs 147g, 23% (46g) 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
Filter Threads
Both the HD Pentax-FA 35mm F2 AL and the Pentax 70mm F2.4 AL L have the same Filter thread size of 49mm.
Below are links to the 49mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the HD Pentax-FA 35mm F2 AL and the Pentax 70mm F2.4 AL L 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 Monochrome, Pentax KF and Pentax K-3 III.
Pentax 70mm F2.4 AL L is also available in Pentax KAF mount.
Focal Range
HD Pentax-FA 35mm F2 AL is a prime lens with fixed focal lenght of 35mm which has an effective (full-frame 35mm equivalent) focal range of
52.5mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 70mm F2.4 AL L is a prime lens with fixed focal lenght of 70mm which has an effective (full-frame 35mm equivalent) focal range of 105mm when used on a APS-C / DX format camera.