The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 16-35mm F2.8L III and the Pentax 12-24mm F4.0 ED AL 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. Canon 16-35mm F2.8L III is the longer of the two lenses at 128mm. The Pentax 12-24mm F4.0 ED AL with a length of 84mm, is 44mm shorter. Besides being longer, the Canon 16-35mm F2.8L III also has a larger diameter of 89mm compared to the Pentax 12-24mm F4.0 ED AL's 88mm 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 12-24mm F4.0 ED AL weighs 430g, 45% (360g) lighter than the Canon 16-35mm F2.8L III's weight of 790g.
Filter Threads
The Canon 16-35mm F2.8L III has a filter size of 82mm whereas the Pentax 12-24mm F4.0 ED AL has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 82mm filters that we recommend you to consider for the Canon 16-35mm F2.8L III:
And these are the 77mm filters that we recommend for the Pentax 12-24mm F4.0 ED AL:
Lens Mounts
The Canon 16-35mm F2.8L III has the Canon EF 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 Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Focal Range
Canon 16-35mm F2.8L III has a focal range of 16-35mm and
2.2X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
25.6 - 56mm.
On the other hand, the 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.
