The lens allows more delicate video work with T number marks. The focus gear ring is installed for follow focus system. You can change the aperture quietly and smoothly with the uncoupled aperture gear rings. Also, distance scale and T numbers are marked on both sides of the lens for convenience. The Samyang 100mm T3.1 has a low T number of T3.1. You can control the lens precisely when shooting under various exposure environment including relatively dark or too bright situations. This lens features 15 lenses in 12 groups including a high refractive lens (HR) and extra low dispersion lens (ED) to minimise colour aberration and unnecessary light dispersion, in order to offer high resolution throughout the image. The Ultra Multi Coating (UMC) is used to optimise light penetration and minimise flare and ghost. With such optical construction, it has 0.307m of minimum focal length to film subjects in a very near distance. There are 9 aperture blades designed to be almost a full circle when the aperture is closed, which expresses starlike ray clearly and beautifully. The frame of the lens is compact and solid since it is made of high-strength aluminium alloy so you can create trustworthy images. Also, detachable petal-shaped hood minimises flare and ghost by sheltering the lens from unnecessary light.