Flange distance (also called flange focal distance or flange back) is the distance from a camera’s lens mount to its sensor or film plane. It is one of the first things to check when you want to put a lens from one system on a camera from another. This chart lists the flange distance and mount diameter of every mount in our database, with links to the cameras and lenses that use each one.
How to read this chart
- Flange distance: the shorter the number, the closer the mount sits to the sensor. Mirrorless mounts are generally on the short end; SLR mounts are on the long end.
- Mount diameter: the inner diameter of the mount opening. It limits how large a lens throat can be, and can matter when adapting a lens from a wider mount to a narrower one.
- Cameras / Lenses: how many of each are registered in our database for that mount. Click a number to open the list filtered to that mount.
| Mount | Flange distance (mm) | Mount diameter (mm) | Cameras | Lenses |
|---|---|---|---|---|
| Nikon Z | 16 | 55 | 15 | 49 |
| Fujifilm X | 17.7 | 44 † | 36 | 51 |
| Canon EF-M | 18 | 47 | 11 | 8 |
| Sony E | 18 | 46.1 | 45 | 80 |
| Micro Four Thirds | 19.25 † | 38 † | 87 | 90 |
| Canon RF | 20 | 54 | 17 | 52 |
| L-Mount | 20 | 51.6 | 19 | 77 |
| Fujifilm G | 26.7 | 65 † | 8 | 20 |
| Four Thirds | 38.67 † | 50 † | 18 | 28 |
| Canon EF | 44 | 54 | 54 | 80 |
| Canon EF-S | 44 | 54 | — ‡ | 19 |
| Sony A | 44.5 | 49.7 | 25 | 43 |
| Nikon F | 46.5 | 44 | 54 | 120 |
† Not confirmed from an official source. The value shown is the one most consistently given by technical references.
‡ Lens-only mount. These lenses fit cameras registered under a related mount (for example, Canon EF-S lenses on EF-S-compatible cameras listed under Canon EF).
Why flange distance matters for adapters
As a general rule, a lens can be adapted to a camera whose mount has a shorter flange distance, because the adapter fills the gap and keeps the lens at the right distance from the sensor. Going the other way usually needs an adapter with extra glass, which can affect image quality. Flange distance is only one part of compatibility: electronic contacts, autofocus drive, lens coverage and mount diameter all matter too. For a full explanation, read our guide What Is Flange Focal Distance, and Why Does It Matter for Lens Adapters?, and use the adapter database to check a specific combination.
About these figures
Flange distance and mount diameter come from manufacturers’ official materials whenever we could confirm them. Where an official figure could not be confirmed, we mark it with † and say so. We update entries when we can verify a correction; to report an error, contact us.