The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 10-24mm f3.5-4.5 II LD and the Pentax 12-24mm F4.0 ED AL for their suitability to various photography scenarios:
Size and Weight Comparison
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. Tamron 10-24mm f3.5-4.5 II LD weighs 406g, which means it is 24g (5%) lighter than the Pentax 12-24mm F4.0 ED AL which has a weight of 430g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Pentax KAF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
Both the Tamron 10-24mm f3.5-4.5 II LD and the Pentax 12-24mm F4.0 ED AL have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Tamron 10-24mm f3.5-4.5 II LD and the Pentax 12-24mm F4.0 ED AL 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 Monochrome, Pentax KF and Pentax K-3 III.
Tamron 10-24mm f3.5-4.5 II LD is also available in Canon EF , Nikon F (DX), Sony Alpha and Canon EF mounts.
Focal Range
Tamron 10-24mm f3.5-4.5 II LD has a focal range of 10-24mm and
2.4X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
15-36mm when used on a APS-C / DX format camera.
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.