The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 70-300mm F4-5.6 DG and the Sony 75-300mm F4.5-5.6 for their suitability to various photography scenarios:
Size and Weight Comparison
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 75-300mm F4.5-5.6 weighs 460g, 16% (90g) lighter than the Sigma 70-300mm F4-5.6 DG's weight of 550g.
Below you can find the dimension and weight table of the Telephoto Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Telephoto Lenses in Sony Alpha Mount for Size Comparison
Filter Threads
The Sigma 70-300mm F4-5.6 DG has a filter size of 58mm whereas the Sony 75-300mm F4.5-5.6 has a 55mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Sigma 70-300mm F4-5.6 DG:
And these are the 55mm filters that we recommend for the Sony 75-300mm F4.5-5.6:
Lens Mounts
Both the Sigma 70-300mm F4-5.6 DG and the Sony 75-300mm 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.
Sigma 70-300mm F4-5.6 DG is also available in Canon EF , Nikon F (FX), Pentax KAF, Sony Alpha, Sigma SA, Canon EF, Nikon F (FX), Pentax KAF and Sigma SA mounts.
Focal Range
Sigma 70-300mm F4-5.6 DG has a focal range of 70-300mm and
4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
105 - 450mm.
On the other hand, the Sony 75-300mm F4.5-5.6 has a focal range of 75-300mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 112.5 - 450mm.