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 18-300 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 18-300 F3.5-6.3 DC OS HSM is the longer of the two lenses at 102mm. The Sigma 18-250mm F3.5-6.3 DC OS HSM with a length of 101mm, is 1mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 79mm.
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 18-300 F3.5-6.3 DC OS HSM weighs 585g, 6% (43g) lighter than the Sigma 18-250mm F3.5-6.3 DC OS HSM's weight of 628g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Canon EF Mount for size comparison purposes.
Super Telephoto Lenses in Canon EF Mount for Size Comparison
Filter Threads
Both the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Sigma 18-300 F3.5-6.3 DC OS HSM have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Sigma 18-300 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 Canon T8i, Canon 90D and Canon SL3.
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.
Sigma 18-300 F3.5-6.3 DC OS HSM is also available in Nikon F (DX) , Pentax KAF3, Sigma SA and Sony Alpha mounts.
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
28.8-400mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 18-300 F3.5-6.3 DC OS HSM has a focal range of 18-300mm and 16.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-480mm when used on a APS-C / DX format camera.