Samyang 35mm T1.5 AS UMC VDSLR II Lens.
The new Mark II (Mk 2) versions feature revised placement of the focus and aperture gearing, so all newest lenses have the gearing in the same place for convenience on rigs and professional follow focus systems.
This VDSLR (Video DSLR) version has been developed primarily for professional cine / movie making purposes. The VDSLR version feature follow focus gearing and decoupled aperture, which allow the user to smoothly and quietly change focus and aperture / depth of field whist filming, and link to professional follow focus cam systems.
The Samyang is rated in T-Stops rather than F-stops which is usual for movie camera lenses. F-stop number expresses the speed of the lens on the assumption that lens transmits 100% of the incident light. The T-number expresses the actual light transmission, which is more accurate, and is the standard in professional cine lenses.