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 Samyang 300mm f6.3 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 Samyang 300mm f6.3 with a length of 74mm, is 285mm shorter. Besides being longer, the Sony FE 400mm F2.8 GM also has a larger diameter of 158mm compared to the Samyang 300mm f6.3's 65mm 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. Samyang 300mm f6.3 weighs 318g, 89% (2577g) lighter than the Sony FE 400mm F2.8 GM's weight of 2895g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Sony E Mount for size comparison purposes.
Super Telephoto Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Sony FE 400mm F2.8 GM and the Samyang 300mm f6.3 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX5, Sony A7R VI and Sony A7 V.
Samyang 300mm f6.3 is also available in Canon EF-M , Fujifilm X and Micro Four Thirds mounts.
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 Samyang 300mm f6.3 is a prime lens with fixed focal lenght of 300mm which has an effective (full-frame 35mm equivalent) focal range of 450mm when used on a APS-C / DX format camera.
