The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax smc 16-50mm F2.8 ED and the OM System 12-40mm F2.8 PRO II 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 smc 16-50mm F2.8 ED is the longer of the two lenses at 99mm. The OM System 12-40mm F2.8 PRO II with a length of 84mm, is 15mm shorter. Besides being longer, the Pentax smc 16-50mm F2.8 ED also has a larger diameter of 84mm compared to the OM System 12-40mm F2.8 PRO II's 70mm 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. OM System 12-40mm F2.8 PRO II weighs 382g, 32% (183g) lighter than the Pentax smc 16-50mm F2.8 ED's weight of 565g.
Filter Threads
The Pentax smc 16-50mm F2.8 ED has a filter size of 77mm whereas the OM System 12-40mm F2.8 PRO II has a 62mm 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 smc 16-50mm F2.8 ED:
And these are the 62mm filters that we recommend for the OM System 12-40mm F2.8 PRO II:
Lens Mounts
The Pentax smc 16-50mm F2.8 ED has the Pentax KAF2 lens mount whereas the OM System 12-40mm F2.8 PRO II has the Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Pentax KAF2 Mount and OM System OM-3 Astro, OM System OM-5 II and OM System OM-3 for the Micro Four Thirds Mount.
Focal Range
Pentax smc 16-50mm F2.8 ED 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 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.
