Canon A-1 Instructions Manual page 17

In the case of an FD lens which has a
chrome Breech-lock mount ring or of
an FL lens :
Mo un ting
1. Make sure the Breech-lock ring is locked
so that it cannot be tumed.
It will not
mount o nto the camera otherwise.
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 t he camera body and turn the
Breech-lock ring clockwise until it is
t ight.
Dismounting
l. Turn the Breech-lock ring counterclock-
wise until it stops.
2. Pull the lens o ut from the camera body.
-17-
When removing a le ns, take special care not
to damage the protruding pins and levers
on the rear. With the exception of the F ish-
eye 7 .5mm lens, always put a lens down
with the rear facing up.
Whenever you mount an FD lens on t he A-1,
its
maximum
aper ture is automatically
transmitted to t he camera's AE circuit. Even
if you swi tch t o a n F D lens of a differen t
maximum aper t ure, the Jnount ing procedure
is the same as that described above and re-
quires no adj ustme nt.
All five AE modes are possible wit h an FD
lens. Sec SETTING T
HE LENS FOR AE
PHOTOGR APHY. Of the five AE modes,
only st opped-down AE is possible with a n
FL
lens .