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Canon RF mount: 20 mm flange focal distance, 54 mm diameter
What is the Canon RF flange focal distance and throat diameter? · Standard part · basis: Published numbers only (sources per row); no bayonet geometry is published, so no file
Also called: canon rf flange distance, rf mount diameter, canon rf mount dimensions, rf mount 54mm, ef to rf adapter thickness
Exact dimensions. True size, with no printing tolerance added.
- sizes
- 3 in table
Notes
- Flange focal distance is the distance from the mount's reference face to the image plane; adapters and extension tubes must add exactly the difference between two mounts' flange distances to keep infinity focus.
- RF replaced EF on Canon's mirrorless bodies: the 54 mm diameter stayed, and the flange distance went from 44 mm to 20 mm, which is why an EF-to-RF adapter is 24 mm thick.
- No file: the bayonet's lug widths, angles, depths and locking geometry are not published by the maker, so nothing is drawn. Only the published numbers are given.
Canon RF mount: 20 mm flange focal distance, 54 mm diameter size chart
| parameter | value | from |
|---|---|---|
| flange focal distance | 20 mm | Canon (lens mount guide) |
| throat / inner diameter | 54 mm (mount diameter) | Canon U.S.A. press release, 2018 |
| coupling | bayonet | — |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Canon | Camera lens mount guide (RF: 20 mm flange distance) | web | Publisher's page; dimensions are facts |
| Canon U.S.A. | Canon introduces four RF mount lenses (press release, 5 Sep 2018): RF mount 54 mm diameter | web | Publisher's page; dimensions are facts |
| Wikipedia | Flange focal distance (table of mounts) | web | CC BY-SA 4.0 (text); dimensions are facts |
Xem scan
File coming
No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=canon-rf-mount
Fits with
Questions
What is the Canon RF flange distance?
20 mm, with a 54 mm mount diameter (Canon).
Why is the EF-to-RF adapter 24 mm thick?
EF has a 44.00 mm flange distance and RF 20 mm: 44 − 20 = 24 mm.