The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony DT 18-55mm F3.5-5.6 SAM and the Sigma 17-50mm F2.8 EX DC OS HSM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 17-50mm F2.8 EX DC OS HSM is the longer of the two lenses at 92mm. The Sony DT 18-55mm F3.5-5.6 SAM with a length of 69mm is 23mm shorter. Besides being longer, the Sigma 17-50mm F2.8 EX DC OS HSM also has a larger diameter of 84mm compared to Sony DT 18-55mm F3.5-5.6 SAM's 70mm diameter.
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. Sony DT 18-55mm F3.5-5.6 SAM weighs 210g, which means it is 355g (62%) lighter than the Sigma 17-50mm F2.8 EX DC OS HSM which has a weight of 565g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Standard Zoom Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both Sony DT 18-55mm F3.5-5.6 SAM and Sigma 17-50mm F2.8 EX DC OS 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 17-50mm F2.8 EX DC OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (DX) mounts.
Focal Range
Sony DT 18-55mm F3.5-5.6 SAM has a focal range of 18-55mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-82.5mm when used on a APS-C / DX format camera. Sigma 17-50mm F2.8 EX DC OS HSM has a focal range of 17-50mm and 2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 25.5-75mm when used on a APS-C / DX format camera.