【F1.8 large Aperture and 7 circular aperture blades】Flexible use of F1.8 large aperture, easy to obtain a soft and beautiful blur effect. In low light environment you can also use a low sensitivity and high shutter for shooting.With 7 circular aperture blades, circular dispersion spots can be shot, and 14 star awn. | 【USB Firmware Upgrade 】Equipped with USB interface, you can download the latest firmware from Yongnuo official website to upgrade the lens. | 【8 elements in 7 groups lens construction】 Adopts 7 groups of 8 pieces of optical structure design, nanometer multi-layer coating process of lens can effectively improve the light transmittance and inhibit the ghost image and glare of backlight. | 【AF/MF Focus Mode Switch and Low dispersion glass lens】 Auto focus and manual focus are supported,you can choose the focus mode according to your shooting requirements. Adopts one low dispersion glass lens,which not only better suppress the dispersion problem, but also further improve the secondary spectrum. | 【Silent Stepping Motor and electronic focus rings】This quiet Digital Stepping Motor(DSM ) drive system makes the lenses ideal for use when shooting video. Adopts electronic focus rings, supplemented by appropriate damping, which can provide smooth manual focus experience of high precision.