[Easy-to-Use Warm Tips] - Fully manual lens has no electronic contacts for focusing. Switch the camera to full manual (M) mode immediately after installation, otherwise the "no lens" error may be triggered; If the error still occurs, you need to enable the "Release shutter without lens" option in the camera menu. [Manual Focus Experience] - Tailored for photographers who pursue the ultimate, the 420-800mm F8.3 lens adopts a fully manual focus design, requiring photographers to carefully adjust parameters such as shutter speed, ISO and aperture before shooting. [Telephoto Zoom Lens] - Features include precision manual focus with a large focus ring design and an internal focus mechanism, UMC technology to minimize aberrations and flare. The aperture automatically adjusts based on focal length (f/8.3 at 420mm, f/16 at 800mm), and it is compatible with 62mm filters and EF/EF-S mounts. [Compatibility with Canon EF/EF-S Mount] - Lightdow 420-800mm f8.3 telephoto lens is perfectly compatible with for Canon EOS Rebel T8i/T7i/T7/T6s/T6i/T6/T5i/T5/T4i/T3i/T3/T2i/T1i/XSi/XS/SL3/SL2/SL1(100D) & Digital Rebel/XTi/XT/T100(4000D) & EOS 90D/80D/77D/70D/60D/50D/40D/30D/20D/10D/7D Mark II/7D/6D Mark II/6D/5DS R/5DS/5D Mark IV/5D Mark III/5D Mark II/5D & EOS-1D X Mark III/1D X Mark II/1D X/1Ds Mark III/1Ds Mark II/1Ds/1D Mark IV/1D Mark III/1D Mark II/Mark II N/1D. [Capture Capabilities] - 420-800mm manual focus telephoto lens excels at capturing detailed images of distant subjects, effectively bringing remote objects closer. It is ideal for photographing the moon, wildlife, birds, buildings, airplanes, landscapes, and more. The aperture range is F8.3-16, and it automatically adjusts with the focal length. Consequently, the camera cannot set the aperture value of the manual lens, resulting in the display of F00/F-- on the camera.

Focal length: 420-800 mm

Aperture: f/8.3-16 

Focus Type: Manual Focus

Auto Focus: No

Minimum Focus Distance: 3 Meters