This telephoto zoom lens is an ideal choice for small or far away things, e.g. birds, wildlife, airplanes, etc. Focal length: 420-800mm zoom lens With a construction of 4 elements in 2 groups It is lightweight (550 g) and compact (only 29.8 cm long), and it is at the closest focus distance 1.6 metres. Focusing: manual helical (rotating) operation (not AF compatible) Note: This is a manual lens that could not be detected by the camera. Please switch your camera to M mode and use the lens by manual focus.