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 Pentax 12-24mm F4.0 ED AL for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.PENTAX15-30mm F2.8 ED WR is the longer of the two lenses at 144mm. The Pentax 12-24mm F4.0 ED AL with a length of 84mm is 60mm shorter. Besides being longer, the PENTAX15-30mm F2.8 ED WR also has a larger diameter of 99mm compared to Pentax 12-24mm F4.0 ED AL's 88mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Pentax 12-24mm F4.0 ED AL weighs 430g, 58% (610g) lighter than the PENTAX15-30mm F2.8 ED WR's weight of 1040g.
Both PENTAX15-30mm F2.8 ED WR has the Pentax KAF3 lens mount whereas the Pentax 12-24mm F4.0 ED AL has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax KF, Pentax K-3 III and Pentax K-1 II for the Pentax KAF3 Mount and Pentax KF, Pentax K-3 III and Pentax KP for the Pentax KAF Mount.
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 an 35mm (FF) equivalent of 22.5 - 45mm.
Pentax 12-24mm F4.0 ED AL has a focal range of 12-24mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 18-36mm when used on a APS-C / DX format camera.