The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Olympus ED 7-14mm F2.8 PRO and the Pentax 17-70mm F4.0 AL SDM 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. Olympus ED 7-14mm F2.8 PRO is the longer of the two lenses at 106mm. The Pentax 17-70mm F4.0 AL SDM with a length of 94mm, is 12mm shorter. Besides being longer, the Olympus ED 7-14mm F2.8 PRO also has a larger diameter of 79mm compared to the Pentax 17-70mm F4.0 AL SDM's 75mm 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 17-70mm F4.0 AL SDM weighs 485g, 9% (49g) lighter than the Olympus ED 7-14mm F2.8 PRO's weight of 534g.
Lens Mounts
The Olympus ED 7-14mm F2.8 PRO has the Micro Four Thirds lens mount whereas the Pentax 17-70mm F4.0 AL SDM 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 , and for the Pentax KAF3 Mount.
Focal Range
Olympus ED 7-14mm F2.8 PRO has a focal range of 7-14mm and
2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
14-28mm when used on a FourThirds format camera.
On the other hand, the 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.
