The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Irix 11mm F4 and the Pentax 15mm F4 ED 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. Irix 11mm F4 is the longer of the two lenses at 118mm. The Pentax 15mm F4 ED AL L with a length of 40mm, is 78mm shorter. Besides being longer, the Irix 11mm F4 also has a larger diameter of 103mm compared to the Pentax 15mm F4 ED 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 15mm F4 ED AL L weighs 189g, 76% (601g) lighter than the Irix 11mm F4's weight of 790g.
Lens Mounts
The Irix 11mm F4 has the Pentax KAF3 lens mount whereas the Pentax 15mm F4 ED AL L has the Pentax KAF 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 KAF3 Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Irix 11mm F4 is also available in the Canon EF and Nikon F (FX) mounts.
Focal Range
Irix 11mm F4 is a prime lens with fixed focal lenght of 11mm.
On the other hand, the Pentax 15mm F4 ED AL L is a prime lens with fixed focal lenght of 15mm which has an effective (full-frame 35mm equivalent) focal range of 22.5mm when used on a APS-C / DX format camera.
