The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 500mm F8 Reflex and the Sigma 50-500mm F4.5-6.3 DG OS HSM 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. Sigma 50-500mm F4.5-6.3 DG OS HSM is the longer of the two lenses at 219mm. The Sony 500mm F8 Reflex with a length of 118mm, is 101mm shorter. Besides being longer, the Sigma 50-500mm F4.5-6.3 DG OS HSM also has a larger diameter of 104mm compared to the Sony 500mm F8 Reflex's 89mm 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 500mm F8 Reflex weighs 665g, which means it is 1305g (66%) lighter than the Sigma 50-500mm F4.5-6.3 DG OS HSM which has a weight of 1970g.
Filter Threads
The Sony 500mm F8 Reflex has a filter size of 55mm whereas the Sigma 50-500mm F4.5-6.3 DG OS HSM has a 95mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sony 500mm F8 Reflex:
And these are the 95mm filters that we recommend for the Sigma 50-500mm F4.5-6.3 DG OS HSM:
Lens Mounts
Both the Sony 500mm F8 Reflex and the Sigma 50-500mm F4.5-6.3 DG OS HSM 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 50-500mm F4.5-6.3 DG OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (FX) mounts.
Focal Range
Sony 500mm F8 Reflex is a prime lens with fixed focal lenght of 500mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
750mm.
On the other hand, the Sigma 50-500mm F4.5-6.3 DG OS HSM has a focal range of 50-500mm and 10.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 75 - 750mm.
