The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 15-30mm f2.8 VC USD and the Sony DT 11-18mm F4.5-5.6 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. Tamron 15-30mm f2.8 VC USD is the longer of the two lenses at 145mm. The Sony DT 11-18mm F4.5-5.6 with a length of 81mm, is 64mm shorter. Besides being longer, the Tamron 15-30mm f2.8 VC USD also has a larger diameter of 98mm compared to the Sony DT 11-18mm F4.5-5.6's 83mm 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. Sony DT 11-18mm F4.5-5.6 weighs 360g, 67% (740g) lighter than the Tamron 15-30mm f2.8 VC USD's weight of 1100g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both the Tamron 15-30mm f2.8 VC USD and the Sony DT 11-18mm F4.5-5.6 has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A99 II, Sony A68 and Sony A77 II.
Tamron 15-30mm f2.8 VC USD is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Tamron 15-30mm f2.8 VC USD has a focal range of 15-30mm and
2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
22.5 - 45mm.
On the other hand, the Sony DT 11-18mm F4.5-5.6 has a focal range of 11-18mm and 1.6X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 16.5-27mm when used on a APS-C / DX format camera.