The type of photography that you are planning to use is an important decision factor. Here we have evaluated the OM System 12-40mm F2.8 PRO II and the Pentax 16-85mm F3.5-5.6 ED DC WR 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 16-85mm F3.5-5.6 ED DC WR is the longer of the two lenses at 94mm. The OM System 12-40mm F2.8 PRO II with a length of 84mm, is 10mm shorter. Besides being longer, the Pentax 16-85mm F3.5-5.6 ED DC WR also has a larger diameter of 78mm compared to the OM System 12-40mm F2.8 PRO II's 70mm diameter.
Below you can find a scaled side-by-side image of OM System 12-40mm F2.8 PRO II and Pentax 16-85mm F3.5-5.6 ED DC WR to get a better idea of how their sizes compare in real life.
Comparison image of the OM System 12-40mm F2.8 PRO II and the Pentax 16-85mm F3.5-5.6 ED DC WR Size and Weight 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. OM System 12-40mm F2.8 PRO II weighs 382g, which means it is 106g (21%) lighter than the Pentax 16-85mm F3.5-5.6 ED DC WR which has a weight of 488g.
Filter Threads
The OM System 12-40mm F2.8 PRO II has a filter size of 62mm whereas the Pentax 16-85mm F3.5-5.6 ED DC WR has a 72mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the OM System 12-40mm F2.8 PRO II:
And these are the 72mm filters that we recommend for the Pentax 16-85mm F3.5-5.6 ED DC WR:
Lens Mounts
The OM System 12-40mm F2.8 PRO II has the Micro Four Thirds lens mount whereas the Pentax 16-85mm F3.5-5.6 ED DC WR has the Pentax KAF3 lens mount . Some of the latest released cameras that are compatible with these mounts are OM System OM-3 Astro , OM System OM-5 II and OM System OM-3 for the Micro Four Thirds Mount and Pentax K-3 III Mono , Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount.
Focal Range
OM System 12-40mm F2.8 PRO II has a focal range of 12-40mm and
3.3X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
24-80mm when used on a FourThirds format camera.
On the other hand, the Pentax 16-85mm F3.5-5.6 ED DC WR has a focal range of 16-85mm and 5.3X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 24-127.5mm when used on a APS-C / DX format camera.
