The type of photography that you are planning to use is an important decision factor. Here we have evaluated the PENTAX15-30mm F2.8 ED WR 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. PENTAX15-30mm F2.8 ED WR is the longer of the two lenses at 144mm. The Sigma 12-24mm F4.5-5.6 EX DG HSM with a length of 103mm, is 41mm shorter. Besides being longer, the PENTAX15-30mm F2.8 ED WR also has a larger diameter of 99mm compared to the Sigma 12-24mm F4.5-5.6 EX DG HSM's 87mm 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. Sigma 12-24mm F4.5-5.6 EX DG HSM weighs 600g, 42% (440g) lighter than the PENTAX15-30mm F2.8 ED WR's weight of 1040g.
Lens Mounts
The PENTAX15-30mm F2.8 ED WR has the Pentax KAF3 lens mount whereas the Sigma 12-24mm F4.5-5.6 EX DG HSM has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount and Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
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
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.
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.