The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 135mm F1.8 DG HSM and the Sony FE 400mm F2.8 GM 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. Sony FE 400mm F2.8 GM is the longer of the two lenses at 359mm. The Sigma 135mm F1.8 DG HSM with a length of 141mm, is 218mm shorter. Besides being longer, the Sony FE 400mm F2.8 GM also has a larger diameter of 158mm compared to the Sigma 135mm F1.8 DG HSM's 91mm diameter.
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Below you can find a scaled side-by-side image of Sigma 135mm F1.8 DG HSM and Sony FE 400mm F2.8 GM to get a better idea of how their sizes compare in real life.
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. Sigma 135mm F1.8 DG HSM weighs 1130g, which means it is 1765g (60%) lighter than the Sony FE 400mm F2.8 GM which has a weight of 2895g.
Filter Threads
The Sigma 135mm F1.8 DG HSM has a filter size of 82mm whereas the Sony FE 400mm F2.8 GM has a 41mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 82mm filters that we recommend you to consider for the Sigma 135mm F1.8 DG HSM:
And these are the 41mm filters that we recommend for the Sony FE 400mm F2.8 GM:
Lens Mounts
Both the Sigma 135mm F1.8 DG HSM and the Sony FE 400mm F2.8 GM has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A9 III, Sony A7C Mark II and Sony A7CR.
Sigma 135mm F1.8 DG HSM is also available in Sigma SA , Nikon F (FX) and Canon EF mounts.
Focal Range
Sigma 135mm F1.8 DG HSM is a prime lens with fixed focal lenght of 135mm.
On the other hand, the Sony FE 400mm F2.8 GM is a prime lens with fixed focal lenght of 400mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 600mm.