The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-35mm F1.8 DC HSM and the Sony DT 18-55mm F3.5-5.6 SAM II 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 18-35mm F1.8 DC HSM is the longer of the two lenses at 121mm. The Sony DT 18-55mm F3.5-5.6 SAM II with a length of 69mm, is 52mm shorter. Besides being longer, the Sigma 18-35mm F1.8 DC HSM also has a larger diameter of 78mm compared to the Sony DT 18-55mm F3.5-5.6 SAM II's 72mm 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. Sony DT 18-55mm F3.5-5.6 SAM II weighs 222g, 72% (588g) lighter than the Sigma 18-35mm F1.8 DC HSM's weight of 810g.
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 the Sigma 18-35mm F1.8 DC HSM and the Sony DT 18-55mm F3.5-5.6 SAM II 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 18-35mm F1.8 DC HSM is also available in Canon EF , Pentax KAF, Sigma SA and Nikon F (DX) mounts.
Focal Range
Sigma 18-35mm F1.8 DC HSM has a focal range of 18-35mm and 1.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-52.5mm when used on a APS-C / DX format camera. Sony DT 18-55mm F3.5-5.6 SAM II 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.