-Aperture Range: f/2.8 to f/22 -Three Aspherical Elements -Three Low Dispersion Elements -Anti-Reflective Multi-Layer Lens Coating -SD-M AF Motor, Internal Focusing -One-Touch Focus Clutch Mechanism -Water-Repellent Top Coating -9-Blade Diaphragm Product Features High-Light Features Ultra-wide 11-20mm focal length Ideal for shooting landscapes, interiors, nightscape, group shots, weddings. Constant maximum aperture of f/2.8 Great performance in low light conditions, exceptional depth of field control and easy manual management. Valuable feature for still and video shooters. Excellent optical performance Edge-to-edge sharpness, reduced flares and ghosting, excellent contrast. Improved optical resolution. Improved AF accuracy by updating the firmware Internal Focus No problems with lens balancing and using graduated or polarizing filters. Water-repellent coating Easy to wipe and maintain the front element clean. One-touch Focus Clutch mechanism Easy AF/MF switching without interruption of the shooting process. Greatly balanced cost performance Reasonable pricing compared to high level of performance. For Video Content Production The Tokina atx-i 11-20mm F2.8 CF is suggested for videographers and film makers in mind who shoot both stills and video professionally, featuring the following advantages for such a kind of users. Wide cinematic angle enough to feel confident in small places. Minimized focus breathing ? the subject framing does not show big change when focus is adjusted from near to far. Natural footage - the image is not distorted when panning due to very low distortion performance. Constant aperture to use full zoom range while you are filming. Excellent optical performance. The Tokina atx-i 11-20mm F2.8 CF is a perfect match to use with gimbal. Ideal wide angle fitting cinematic standards. Light weight. Zooming abilities that allow user to shoot in different angles using the same lens. Since the overall length does not change thanks to internal type of focusing, there is no need to do gimbal calibration every time the angle of view was changed. Great color rendering and resolution abilities.