DZOFilm Octopus Adapter for EF-Mount Lens to RF-Mount Camera with Active-Locking System (Black)Inspired by Octopus, a smart creature that catches subjects tightly through their tentacles, the DZOFilm Octopus EF to RF Mount Adapter in black finish holds the lens to the camera body tightly as an Octopus does and keeps it secure during use. Plus minus 0. 01mm Tight Tolerance It features a high precision machining. There is no back flange adjustments needed. The infinity focus of the adapter maintains accurate and it weights as light as 154g