The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 16-50mm F2.8 ED PLM AW and the Irix 45mm F1.4 for their suitability to various photography scenarios:
Size and Weight Comparison
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 16-50mm F2.8 ED PLM AW weighs 712g, which means it is 213g (23%) lighter than the Irix 45mm F1.4 which has a weight of 925g.
Filter Threads
Both the Pentax 16-50mm F2.8 ED PLM AW and the Irix 45mm F1.4 have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Pentax 16-50mm F2.8 ED PLM AW has the Pentax KAF4 lens mount whereas the Irix 45mm F1.4 has the Pentax KAF2 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 KAF4 Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF2 Mount.
Irix 45mm F1.4 is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Pentax 16-50mm F2.8 ED PLM AW has a focal range of 16-50mm and
3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
24-75mm when used on a APS-C / DX format camera.
On the other hand, the Irix 45mm F1.4 is a prime lens with fixed focal lenght of 45mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 67.5mm.
