Nikon TC-17E II  type_Developing Tanks Peer into the lensmount side

Peer into the lensmount side and you can see the fixed prism that directs part of the light to the AF sensors

and the microscopically clean surface discourages the accumulation of futher dust

This is an Autographic camera

Carl Zeiss F Sonnar 150mm f2

Nikon TC-17E II &nbsptype_Developing Tanks Peer into the lensmount sideThe Nikon TC 17E II is an autofocus teleconverter designed for select Nikon AF S telephoto lenses (here's Nikon's compatibility list). Provides a 1. 7x focal length boost, loses about a stop and a half of light. In good cosmetic condition, with minor paint and finish wear. Good optics and function. Includes caps.