The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 85mm F1.4 and the Canon 300mm f4.0L IS USM 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 300mm f4.0L IS USM is the longer of the two lenses at 221mm. The Rokinon 85mm F1.4 with a length of 75mm, is 146mm shorter. Besides being longer, the Canon 300mm f4.0L IS USM also has a larger diameter of 90mm compared to the Rokinon 85mm F1.4's 78mm 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. Rokinon 85mm F1.4 weighs 539g, which means it is 651g (54%) lighter than the Canon 300mm f4.0L IS USM which has a weight of 1190g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Canon EF Mount for size comparison purposes.
Telephoto Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Rokinon 85mm F1.4 has a filter size of 72mm whereas the Canon 300mm f4.0L IS USM 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 72mm filters that we recommend you to consider for the Rokinon 85mm F1.4:
And these are the 77mm filters that we recommend for the Canon 300mm f4.0L IS USM:
Lens Mounts
Both the Rokinon 85mm F1.4 and the Canon 300mm f4.0L IS USM 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.
Rokinon 85mm F1.4 is also available in the Four Thirds , Pentax KAF, Sony Alpha, Samsung NX and Nikon F (FX) mounts.
Focal Range
Rokinon 85mm F1.4 is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
136mm.
On the other hand, the Canon 300mm f4.0L IS USM is a prime lens with fixed focal lenght of 300mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 480mm.
