NIKON AF-S TELECONVERTER TC800-1.25E ED
1.25× rear teleconverter for Nikon F
JP 2013-250290 A — Akiko Furuta
5 ELEMENTS / 3 GROUPS | 1.25× REAR CONVERTER | ALL SPHERICAL
A dedicated converter: it mounts only on lenses made to accept it. A teleconverter has no aperture stop of its own, so it is shown attached to a host lens, where the lens's stop stays the system stop and the focal length and f-number both grow by the converter's factor.