The Canon CN-E 20mm T1.5 L F Cinema Prime Lens is a manual focus prime lens that covers Full Frame and Super 35 sensor formats. The lens offers a maximum aperture of T1.5, useful when shooting in low light situations or when you want to capture that exceedingly shallow depth of field look. It has an 11-blade iris that provides round, out-of-focus highlights for a natural looking bokeh. The lens barrel features 300? of stepless, smooth rotation from close focus to infinity, giving you a high degree of precision and consistent focus. The lens features standard cine lens gears and is designed to minimize focus breathing and also has innovative glass construction that counteracts barrel expansion and contraction to avoid temperature-induced marking discrepancies. It's dual focus, with markings on both sides of the barrel. The rear markings are on an angled surface, making it readable form either side of the camera. It also has a dust- and water-resistant housing to minimize maintenance during normal use.