The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 10-20mm F4-5.6 EX DC HSM and the Sigma 8-16mm F4.5-5.6 DC HSM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sigma 8-16mm F4.5-5.6 DC HSM is the longer of the two lenses at 106mm. The Sigma 10-20mm F4-5.6 EX DC HSM with a length of 81mm, is 25mm shorter. On the other hand, the Sigma 10-20mm F4-5.6 EX DC HSM has a larger diameter of 84mm compared to the Sigma 8-16mm F4.5-5.6 DC HSM's 75mm diameter.
The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Sigma 10-20mm F4-5.6 EX DC HSM weighs 470g, which means it is 85g (15%) lighter than the Sigma 8-16mm F4.5-5.6 DC HSM which has a weight of 555g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Wideangle Zoom Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both the Sigma 10-20mm F4-5.6 EX DC HSM and the Sigma 8-16mm F4.5-5.6 DC HSM has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Sigma 10-20mm F4-5.6 EX DC HSM is also available in Canon EF , Four Thirds, Pentax KAF, Sigma SA and Nikon F (DX) mounts.
Sigma 8-16mm F4.5-5.6 DC HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (DX) mounts.
Focal Range
Sigma 10-20mm F4-5.6 EX DC HSM has a focal range of 10-20mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-30mm when used on a APS-C / DX format camera. Sigma 8-16mm F4.5-5.6 DC HSM has a focal range of 8-16mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 12-24mm when used on a APS-C / DX format camera.