The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 70-300mm F4-5.6 DG and the Sigma 18-250mm F3.5-6.3 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. Sigma 70-300mm F4-5.6 DG is the longer of the two lenses at 122mm. The Sigma 18-250mm F3.5-6.3 DC OS HSM with a length of 101mm, is 21mm shorter. On the other hand, the Sigma 18-250mm F3.5-6.3 DC OS HSM has a larger diameter of 79mm compared to the Sigma 70-300mm F4-5.6 DG's 77mm 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 70-300mm F4-5.6 DG weighs 550g, which means it is 78g (12%) lighter than the Sigma 18-250mm F3.5-6.3 DC OS HSM which has a weight of 628g.
Filter Threads
The Sigma 70-300mm F4-5.6 DG has a filter size of 58mm whereas the Sigma 18-250mm F3.5-6.3 DC OS HSM has a 72mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Sigma 70-300mm F4-5.6 DG:
And these are the 72mm filters that we recommend for the Sigma 18-250mm F3.5-6.3 DC OS HSM:
Lens Mounts
Both the Sigma 70-300mm F4-5.6 DG and the Sigma 18-250mm F3.5-6.3 DC OS HSM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K.
Sigma 70-300mm F4-5.6 DG is also available in the Nikon F (FX) , Pentax KAF, Sony Alpha, Sigma SA, Canon EF, Nikon F (FX), Pentax KAF, Sony Alpha and Sigma SA mounts.
Sigma 18-250mm F3.5-6.3 DC OS HSM is also available in Canon EF , Nikon F (DX), Pentax KAF3, Sony Alpha, Sigma SA, Nikon F (DX), Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 70-300mm F4-5.6 DG has a focal range of 70-300mm and
4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
112 - 480mm.
On the other hand, the 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 28.8-400mm when used on a APS-C / DX format camera.
