The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 100-400mm f4.5-5.6L IS II USM 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. Canon 100-400mm f4.5-5.6L IS II USM is the longer of the two lenses at 193mm. The Samyang 300mm f6.3 with a length of 74mm, is 119mm shorter. Besides being longer, the Canon 100-400mm f4.5-5.6L IS II USM also has a larger diameter of 94mm 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 260g, 83% (1330g) lighter than the Canon 100-400mm f4.5-5.6L IS II USM's weight of 1590g.
Filter Threads
The Canon 100-400mm f4.5-5.6L IS II USM has a filter size of 77mm whereas the Samyang 300mm f6.3 has a 26mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Canon 100-400mm f4.5-5.6L IS II USM:
And these are the 26mm filters that we recommend for the Samyang 300mm f6.3:
Lens Mounts
Both the Canon 100-400mm f4.5-5.6L IS II USM and the Samyang 300mm f6.3 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K.
Samyang 300mm f6.3 is also available in Nikon F (DX) , Four Thirds and Sony Alpha mounts.
Focal Range
Canon 100-400mm f4.5-5.6L IS II USM has a focal range of 100-400mm and
4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
160 - 640mm.
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 480mm when used on a APS-C / DX format camera.
