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 HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye 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 HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye with a length of 70mm, is 48mm shorter. Besides being longer, the Irix 11mm F4 also has a larger diameter of 103mm compared to the HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye's 68mm 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. HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye weighs 317g, 59% (473g) lighter than the Irix 11mm F4's weight of 790g.
Lens Mounts
The Irix 11mm F4 has the Pentax KAF3 lens mount whereas the HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye 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 HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye has a focal range of 10-17mm and 1.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-25.5mm when used on a APS-C / DX format camera.
