The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax D FA 70-200mm F2.8ED and the Sigma 50-150mm F2.8 EX DC 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. Pentax D FA 70-200mm F2.8ED is the longer of the two lenses at 203mm. The Sigma 50-150mm F2.8 EX DC OS HSM with a length of 198mm, is 5mm shorter. Besides being longer, the Pentax D FA 70-200mm F2.8ED also has a larger diameter of 92mm compared to the Sigma 50-150mm F2.8 EX DC OS HSM's 86mm 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. Sigma 50-150mm F2.8 EX DC OS HSM weighs 1350g, 23% (405g) lighter than the Pentax D FA 70-200mm F2.8ED's weight of 1755g.
Filter Threads
Both the Pentax D FA 70-200mm F2.8ED and the Sigma 50-150mm F2.8 EX DC OS HSM have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Pentax D FA 70-200mm F2.8ED has the Pentax KAF3 lens mount whereas the Sigma 50-150mm F2.8 EX DC OS HSM has the Canon EF 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 KAF3 Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Sigma 50-150mm F2.8 EX DC OS HSM is also available in Nikon F (DX) and Sigma SA mounts.
Focal Range
Pentax D FA 70-200mm F2.8ED has a focal range of 70-200mm and
2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
105 - 300mm.
On the other hand, the Sigma 50-150mm F2.8 EX DC OS HSM has a focal range of 50-150mm and 3.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 80-240mm when used on a APS-C / DX format camera.
