Flange Locking Mechanism: Threaded flange-locking structure ensures secure, shake-free installation Precision Infinity Focus: CNC machined and assembled for accurate focus at infinity Premium Metal Construction: Brass and aluminum alloy for durability and light weight Unable to adjust the lens's electronic aperture;Manual focus only; No lens EXIF data transmission; Enable "Shoot without lens" if shutter cannot be released or "No lens" warning appears For any questions regarding product use, please see the tutorial video or leave a message for help