The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Sigma 18-125mm F3.8-5.6 DC HSM for their suitability to various photography scenarios:
Size and Weight Comparison
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 18-250mm F3.5-6.3 DC OS HSM weighs 470g, which means it is 20g (4%) lighter than the Sigma 18-125mm F3.8-5.6 DC HSM which has a weight of 490g.
Filter Threads
The Sigma 18-250mm F3.5-6.3 DC OS HSM has a filter size of 72mm whereas the Sigma 18-125mm F3.8-5.6 DC HSM 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 72mm filters that we recommend you to consider for the Sigma 18-250mm F3.5-6.3 DC OS HSM:
And these are the 62mm filters that we recommend for the Sigma 18-125mm F3.8-5.6 DC HSM:
Lens Mounts
The Sigma 18-250mm F3.5-6.3 DC OS HSM has the Nikon F (DX) lens mount whereas the Sigma 18-125mm F3.8-5.6 DC HSM has the Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and , and for the Pentax KAF3 Mount.
Sigma 18-250mm F3.5-6.3 DC OS HSM is also available in the Canon EF , Pentax KAF3, Sony Alpha, Sigma SA, Canon EF, Nikon F (DX), Pentax KAF3, 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 18-250mm F3.5-6.3 DC OS HSM has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-375mm 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.
