The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye and the Sigma 12-24mm F4.5-5.6 EX DG HSM 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. Sigma 12-24mm F4.5-5.6 EX DG HSM is the longer of the two lenses at 103mm. The HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye with a length of 70mm, is 33mm shorter. Besides being longer, the Sigma 12-24mm F4.5-5.6 EX DG HSM also has a larger diameter of 87mm 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, which means it is 283g (47%) lighter than the Sigma 12-24mm F4.5-5.6 EX DG HSM which has a weight of 600g.
Below you can find the dimension and weight table of the Wideangle Fisheye Zoom Lenses in Pentax KAF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Pentax KAF Mount for Size Comparison
Lens Mounts
Both the HD Pentax-DA 10-17mm F3.5-4.5 ED fisheye and the Sigma 12-24mm F4.5-5.6 EX DG HSM has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Sigma 12-24mm F4.5-5.6 EX DG HSM is also available in Canon EF , Sony Alpha, Sigma SA and Nikon F (FX) mounts.
Focal Range
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.
On the other hand, the Sigma 12-24mm F4.5-5.6 EX DG HSM has a focal range of 12-24mm 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 18 - 36mm.
