The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 400mm F2.8 GM and the Sony FE 85mm F1.4 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 Sony FE 85mm F1.4 GM with a length of 108mm, is 251mm shorter. Besides being longer, the Sony FE 400mm F2.8 GM also has a larger diameter of 158mm compared to the Sony FE 85mm F1.4 GM's 90mm diameter.
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Below you can find a scaled side-by-side image of Sony FE 400mm F2.8 GM and Sony FE 85mm F1.4 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. Sony FE 85mm F1.4 GM weighs 820g, 71% (2075g) lighter than the Sony FE 400mm F2.8 GM's weight of 2895g.
Filter Threads
The Sony FE 400mm F2.8 GM has a filter size of 41mm whereas the Sony FE 85mm F1.4 GM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 41mm filters that we recommend you to consider for the Sony FE 400mm F2.8 GM:
And these are the 77mm filters that we recommend for the Sony FE 85mm F1.4 GM:
Lens Mounts
Both the Sony FE 400mm F2.8 GM and the Sony FE 85mm F1.4 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.
Focal Range
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.
On the other hand, the Sony FE 85mm F1.4 GM is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 127.5mm.