Canon AE-1 Instructions Manual page 18

Dismounting
1. Turn the lens counterclockwise until
it
stops while pressing the lens release button.
2.
Pull the lensout.
When the lens is dismounted, the dia-
phragm blades are locked in a half-closed
position and will not move even if you turn
the lens aperture ring.
Operation with an FD lens which has a
chrome Breech-lock mount ring or with
an FL lens:
Mounting
1 .
Make sure the mount ring i s locked so
that
it
cannot be turned.
2.
Align the red dot of the Breech-lock ring
with the red dot on the camera body above
the camera mount.
3. In this position, fit the rear of the lens
into the camera body and turn the Breech-
lock ring clockwise until
it
is tight.
Dismounting
1. Turn the Breech-lock ring counterclock-
wise until it stops.
2. Pull the lensout from the camera body.