The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-50mm f2.8 XR II LD and the Sony 28-75mm F2.8 SAM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sony 28-75mm F2.8 SAM is the longer of the two lenses at 98mm. The Tamron 17-50mm f2.8 XR II LD with a length of 82mm is 16mm shorter. Besides being longer, the Sony 28-75mm F2.8 SAM also has a larger diameter of 78mm compared to Tamron 17-50mm f2.8 XR II LD's 74mm 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. Tamron 17-50mm f2.8 XR II LD weighs 430g, which means it is 135g (23%) lighter than the Sony 28-75mm F2.8 SAM 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
Both Tamron 17-50mm f2.8 XR II LD and Sony 28-75mm F2.8 SAM 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.
Tamron 17-50mm f2.8 XR II LD is also available in Canon EF , Nikon F (DX) and Pentax KAF mounts.
Tamron 17-50mm f2.8 XR II LD 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. Sony 28-75mm F2.8 SAM has a focal range of 28-75mm and 2.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 42 - 112.5mm.