Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sony 24-70mm F2.8 ZA SSM is the longer of the two lenses at 111mm. The Sony 28-75mm F2.8 SAM with a length of 98mm is 13mm shorter. Besides being longer, the Sony 24-70mm F2.8 ZA SSM also has a larger diameter of 83mm compared to Sony 28-75mm F2.8 SAM's 78mm 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 28-75mm F2.8 SAM weighs 565g, which means it is 390g (69%) lighter than the Sony 24-70mm F2.8 ZA SSM which has a weight of 955g.
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 Sony 28-75mm F2.8 SAM and Sony 24-70mm F2.8 ZA SSM 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.
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.
Sony 24-70mm F2.8 ZA SSM has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 36 - 105mm.