The 12mm T3.1 ED AS IF NCS UMC Cine DS Fisheye Lens for Nikon F Mount from Rokinon is a lens optimized for digital cinematography and as such provides a de-clicked manual aperture for smooth and silent adjustment and unified focus and aperture gears for use with follow focus accessories. Also, focus, aperture, and depth of field markings are on the side of the lens to aid focus pullers who typically operate on the side of the camera. Aperture is measured in absolute T-stops to provide accurate and consistent exposure across lenses and color rendition is matched with other Rokinon cine lenses for consistency.

This fisheye lens provides a 180º diagonal angle of view on full-frame cameras for an ultra-wide angle, distorted perspective that is useful for architectural interiors, landscapes and creative experimentation in any application. The T3.1 maximum aperture is effective in low light situations and enables some measure of shallow depth of field control. 

The lens' optical design consists of 12 lens elements arranged in 8 groups including three elements made of low dispersion ED glass and two aspherical lens elements to minimize coma and chromatic aberrations. Highly effective nano crystal anti-reflection (NCS) coating applied together with UMC coatings improve light transmission and reduce ghosting. Its internal focus system does not extend the front elements during focus and minimizes the effects of lens breathing.