The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-200mm F3.5-6.3 DC OS HSM C and the Sigma 18-125mm F3.8-5.6 DC 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 18-125mm F3.8-5.6 DC HSM is the longer of the two lenses at 89mm. The Sigma 18-200mm F3.5-6.3 DC OS HSM C with a length of 86mm, is 3mm shorter. Besides being longer, the Sigma 18-125mm F3.8-5.6 DC HSM also has a larger diameter of 74mm compared to the Sigma 18-200mm F3.5-6.3 DC OS HSM C's 71mm 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 18-200mm F3.5-6.3 DC OS HSM C weighs 430g, which means it is 60g (12%) lighter than the Sigma 18-125mm F3.8-5.6 DC HSM which has a weight of 490g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Pentax KAF3 Mount for size comparison purposes.
Superzoom Lenses in Pentax KAF3 Mount for Size Comparison
Filter Threads
Both the Sigma 18-200mm F3.5-6.3 DC OS HSM C and the Sigma 18-125mm F3.8-5.6 DC HSM have the same Filter thread size of 62mm.
Below are links to the 62mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 18-200mm F3.5-6.3 DC OS HSM C and the Sigma 18-125mm F3.8-5.6 DC HSM has the same Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with the Pentax KAF3 lenses are , and .
Sigma 18-200mm F3.5-6.3 DC OS HSM C is also available in the Canon EF , Nikon F (DX), Sony Alpha and Sigma SA mounts.
Sigma 18-125mm F3.8-5.6 DC HSM is also available in Sony Alpha mount.
Focal Range
Sigma 18-200mm F3.5-6.3 DC OS HSM C has a focal range of 18-200mm and
11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-300mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 18-125mm F3.8-5.6 DC HSM has a focal range of 18-125mm and 6.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-187.5mm when used on a APS-C / DX format camera.
