Full-Frame - f/1.8 to f/16, Customizable Function Control, Ultra-Quiet DSM Stepping Motor, 7-Blade Circular Diaphragm, 1 Low-Dispersion Lens Element, 1 High Refractive Index Element, Nano-Multilayer Coating, USB-C Firmware Update Port. A short telephoto prime featuring a compact design the 85mm f/1.8Z DF DSM Lens from Yongnuo is designed for full-frame-format Nikon Z-mount mirrorless cameras. The lens's bright f/1.8 design suits working in low-light conditions and enables increased control over depth of field for isolating subject matter. The optical design features nine elements in eight groups incorporates one low dispersion element to reduce chromatic aberrations and color fringing. In addition one high refractive index element reduces spherical aberrations and distortion for increased clarity and definition for sharp image quality. A nano multi-layer coating is applied to each optical surface to suppress flare and ghosting for improved contrast in strong lighting conditions. Balancing the optics is a DSM autofocus stepping motor which promotes fast and quiet focusing performance to suit both photo and video applications.