Canon AV 1 - Manual (Page 20)

Operation with an FD lens which lacks
a chrome Breech-lock mount ring:
Mounting
1. Remove the lens' rear dust cap and the
camera's body cap.
2. Align the projecting red mount position­
ing point on the lens with the red dot
above the camera mount,
3. In this position, apply slight pressure to
the lens, and simply rotate the whole
lens clockwise until it stops and the lens
release button pops out with a click.
whil( Do not press the lens release button v
mounting the lens. Only when this button pops