The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 17-70mm F4.0 AL SDM and the Pentax 16-45mm F4 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. Pentax 17-70mm F4.0 AL SDM is the longer of the two lenses at 94mm. The Pentax 16-45mm F4 ED AL with a length of 92mm, is 2mm shorter. Besides being longer, the Pentax 17-70mm F4.0 AL SDM also has a larger diameter of 75mm compared to the Pentax 16-45mm F4 ED AL's 72mm 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 16-45mm F4 ED AL weighs 356g, 26% (129g) lighter than the Pentax 17-70mm F4.0 AL SDM's weight of 485g.
Filter Threads
Both the Pentax 17-70mm F4.0 AL SDM and the Pentax 16-45mm F4 ED AL have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Pentax 17-70mm F4.0 AL SDM has the Pentax KAF3 lens mount whereas the Pentax 16-45mm F4 ED AL has the Pentax 645AF2 lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Pentax KAF3 Mount and , and for the Pentax 645AF2 Mount.
Focal Range
Pentax 17-70mm F4.0 AL SDM has a focal range of 17-70mm and
4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-105mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 16-45mm F4 ED AL has a focal range of 16-45mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 24-67.5mm when used on a APS-C / DX format camera.
