The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 16-50mm F2.8 ED PLM AW and the Pentax 70mm F2.4 AL L 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. Pentax 16-50mm F2.8 ED PLM AW is the longer of the two lenses at 117mm. The Pentax 70mm F2.4 AL L with a length of 26mm, is 91mm shorter. Besides being longer, the Pentax 16-50mm F2.8 ED PLM AW also has a larger diameter of 84mm compared to the Pentax 70mm F2.4 AL L's 63mm 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 70mm F2.4 AL L weighs 147g, 79% (565g) lighter than the Pentax 16-50mm F2.8 ED PLM AW's weight of 712g.
Filter Threads
The Pentax 16-50mm F2.8 ED PLM AW has a filter size of 77mm whereas the Pentax 70mm F2.4 AL L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Pentax 16-50mm F2.8 ED PLM AW:
And these are the 49mm filters that we recommend for the Pentax 70mm F2.4 AL L:
Lens Mounts
The Pentax 16-50mm F2.8 ED PLM AW has the Pentax KAF4 lens mount whereas the Pentax 70mm F2.4 AL L has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF4 Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Pentax 70mm F2.4 AL L is also available in Pentax KAF mount.
Focal Range
Pentax 16-50mm F2.8 ED PLM AW has a focal range of 16-50mm and
3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
24-75mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 70mm F2.4 AL L is a prime lens with fixed focal lenght of 70mm which has an effective (full-frame 35mm equivalent) focal range of 105mm when used on a APS-C / DX format camera.