Zoom eyepiece

Focal length:7~21mm, 8~24mm

7~21mm   35~52degrees AFOV   18~25mm eye relief
8~24mm   45~60degrees AFOV   18mm eye relief(parfocal)

Remark: Fully multicoated optics, a flip down rubber eyeguard, and is threaded for filters. The zoom ranges from 8mm to 24mm and it is parfocal throughout the zoom range.Such zoom use 7 lens-elements in four groups. At least 6 surfaces are in contact with the air.This is a true "all-in-one" accessory