OLYMPUS M.ZUIKO DIGITAL 1.4x Teleconverter MC-14
1.4× rear teleconverter for Micro Four Thirds
US 2015/0226943 A1, Example 1 — Yasuji Ogata, Yasuharu Yamada
6 ELEMENTS / 3 GROUPS | 1.4× 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.