The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Fujifilm 23mm F2.8 and the Pentax 21mm F3.2 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. Pentax 21mm F3.2 AL L is the longer of the two lenses at 25mm. The Fujifilm 23mm F2.8 with a length of 23mm, is 2mm shorter. Besides being longer, the Pentax 21mm F3.2 AL L also has a larger diameter of 63mm compared to the Fujifilm 23mm F2.8's 62mm 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. Fujifilm 23mm F2.8 weighs 90g, which means it is 50g (35%) lighter than the Pentax 21mm F3.2 AL L which has a weight of 140g.
Filter Threads
The Fujifilm 23mm F2.8 has a filter size of 39mm whereas the Pentax 21mm F3.2 AL L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 39mm filters that we recommend you to consider for the Fujifilm 23mm F2.8:
And these are the 49mm filters that we recommend for the Pentax 21mm F3.2 AL L:
Lens Mounts
The Fujifilm 23mm F2.8 has the Fujifilm X lens mount whereas the Pentax 21mm F3.2 AL L has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Pentax 21mm F3.2 AL L is also available in Pentax KAF mount.
Focal Range
Fujifilm 23mm F2.8 is a prime lens with fixed focal lenght of 23mm which has an effective (full-frame 35mm equivalent) focal range of
34.5mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 21mm F3.2 AL L is a prime lens with fixed focal lenght of 21mm which has an effective (full-frame 35mm equivalent) focal range of 31.5mm when used on a APS-C / DX format camera.
