The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Irix 45mm F1.4 and the PENTAX15-30mm F2.8 ED WR 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. Irix 45mm F1.4 weighs 925g, which means it is 115g (11%) lighter than the PENTAX15-30mm F2.8 ED WR which has a weight of 1040g.
Lens Mounts
The Irix 45mm F1.4 has the Canon EF lens mount whereas the PENTAX15-30mm F2.8 ED WR has the Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with these mounts are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount.
Irix 45mm F1.4 is also available in the Nikon F (FX) and Pentax KAF2 mounts.
Focal Range
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 1.6x crop, it provides a 35mm (FF) equivalent of
72mm.
On the other hand, the PENTAX15-30mm F2.8 ED WR has a focal range of 15-30mm and 2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 22.5 - 45mm.
