Full-Frame - T1.9 to T22, 80mm Front Diameter, 10 Aperture Blades, 0.8 MOD Focus and Aperture Gears, 300° Focus Rotation, Lens Markings in Feet and Meters. Capture high-quality images using a full-frame camera with a Canon RF mount with this NiSi ATHENA PRIME 50mm T1.9 Full-Frame Lens. The lens features 10 aperture blades micro-contrast control and low chromatic aberration to highlight image details without distortion. It has an aperture range of T1.9 to T22 and an 80mm front diameter with minimal focus breathing.The focus ring is capable of rotating 300? for intuitive control. Markings on the lens are fluorescent and in both feet and meters. The lens has a 40.1? horizontal angle of view and a 46mm image circle to capture as many details as possible. An included drop-in filter mount places your lens filters of choice in between your camera sensor and lens body.