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L-Mount: 20 mm flange focal distance, 51.6 mm diameter
What is the L-Mount 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: l mount flange distance, l-mount diameter, leica l mount dimensions, l mount 51.6mm, sigma l mount
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.
- Shared by the L-Mount Alliance makers; full-frame and APS-C lenses use the same mount.
- 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.
L-Mount: 20 mm flange focal distance, 51.6 mm diameter size chart
| parameter | value | from |
|---|---|---|
| flange focal distance | 20 mm | L-Mount Alliance |
| throat / inner diameter | 51.6 mm (diameter) | L-Mount Alliance |
| coupling | bayonet | — |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| L-Mount Alliance | L-Mount overview (51.6 mm diameter, 20 mm flange distance) | 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=l-mount
Questions
What is the L-Mount flange distance?
20 mm, with a 51.6 mm diameter (L-Mount Alliance).