The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax FA 70-210mm F4 ED SDM WR and the Sigma 50-500mm F4.5-6.3 DG OS HSM 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. Sigma 50-500mm F4.5-6.3 DG OS HSM is the longer of the two lenses at 219mm. The Pentax FA 70-210mm F4 ED SDM WR with a length of 175mm, is 44mm shorter. Besides being longer, the Sigma 50-500mm F4.5-6.3 DG OS HSM also has a larger diameter of 104mm compared to the Pentax FA 70-210mm F4 ED SDM WR's 79mm 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 FA 70-210mm F4 ED SDM WR weighs 819g, which means it is 1151g (58%) lighter than the Sigma 50-500mm F4.5-6.3 DG OS HSM which has a weight of 1970g.
Filter Threads
The Pentax FA 70-210mm F4 ED SDM WR has a filter size of 67mm whereas the Sigma 50-500mm F4.5-6.3 DG OS HSM has a 95mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Pentax FA 70-210mm F4 ED SDM WR:
And these are the 95mm filters that we recommend for the Sigma 50-500mm F4.5-6.3 DG OS HSM:
Lens Mounts
The Pentax FA 70-210mm F4 ED SDM WR has the Pentax KAF4 lens mount whereas the Sigma 50-500mm F4.5-6.3 DG OS HSM has the Pentax KAF3 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 , and for the Pentax KAF3 Mount.
Sigma 50-500mm F4.5-6.3 DG OS HSM is also available in Canon EF , Sony Alpha, Sigma SA and Nikon F (FX) mounts.
Focal Range
Pentax FA 70-210mm F4 ED SDM WR has a focal range of 70-210mm and
3.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
105-315mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 50-500mm F4.5-6.3 DG OS HSM has a focal range of 50-500mm and 10.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 75 - 750mm.
