About this item Widely usage, lens itself for T2 mount, can installed on telescope to observe moon, through standard adapter ring, can installed for Canon EF-S mount camera for shooting far distance objects. Has 420‑800MM super telephoto zoom, if matching 2X magnification mirror, focal distance range become 840‑1600mm. 2X magnification lens can double the focal length or magnification. Telephoto lenses good for shooting distant scenery, wildlife, concerts, bird observation, etc. Manual adjustment, all metal structure, multi‑layer MC coating of optical glass, good light transmittance.