# Alpa — Camera mount flange focal distance and adapter feasibility

For Alpa, flange focal distance (mm) is 37.8; mount type is bayonet; throat diameter (mm) is 42, verified against its source on 2026-08-13.

- **Mount name:** Alpa _(verified: appears in the quote below)_
- **Flange focal distance (mm):** 37.8 _(verified: appears in the quote below)_
- **Mount type:** bayonet _(verified: appears in the quote below)_
- **Throat diameter (mm):** 42 _(verified: appears in the quote below)_

## What the source says

> Alpa | bayonet | 37.8 | 42 |

## Source

- https://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

Last verified: 2026-08-13. Review by: 2028-08-12.
Part of [Camera mount flange focal distance and adapter feasibility](https://referencesource.org/camera-lens-body-adapter-compatibility/).