The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 40mm f2.8 STM and the Rokinon 35mm f1.4 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. Rokinon 35mm f1.4 is the longer of the two lenses at 112mm. The Canon 40mm f2.8 STM with a length of 22mm, is 90mm shorter. On the other hand, the Canon 40mm f2.8 STM has a larger diameter of 68mm compared to the Rokinon 35mm f1.4's 63mm 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. Canon 40mm f2.8 STM weighs 130g, which means it is 530g (80%) lighter than the Rokinon 35mm f1.4 which has a weight of 660g.
Filter Threads
The Canon 40mm f2.8 STM has a filter size of 52mm whereas the Rokinon 35mm f1.4 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 52mm filters that we recommend you to consider for the Canon 40mm f2.8 STM:
And these are the 77mm filters that we recommend for the Rokinon 35mm f1.4:
Lens Mounts
Both the Canon 40mm f2.8 STM and the Rokinon 35mm f1.4 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Rokinon 35mm f1.4 is also available in Nikon F (FX) , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
Focal Range
Canon 40mm f2.8 STM is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
64mm.
On the other hand, the Rokinon 35mm f1.4 is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 56mm.