Automatic Diaphragm Control; Manual Diaphragm Control - Canon A-1 Instructions Manual

Automatic Diaphragm Control
When the t\-1 is dire ctly coupled with an FO
lens, diaphragm control is totally automatic.
1 ·:xposure metering is performed . a t . full
aperture whether the lens aperture rmg 1s at
the "A " mark or set to a specific aper1 ure .
At sh u u er release, the diaph ragm auto ma ti-
call y closes down to th e aperture set by th e
camera o r b y you with the AT dial or the
aperture
rin~.
Following shutter
~·c lease ,
th e
lens a uto ma t1cally returns to maximum aper·
tu re .
Manual Diaphragm Control
Th e insertion of m anual accessories or a
macrophoto coupler
betwe~n
the came.ra
and an FD lens requires settmg the lens for
manual diaphragm control befo!e sto pi;>ed·
down metering is possible. The mstruc t1ons
for the various accessories involved will tell
y ou whe ther or not this is necessary.
-80-
All FD lenses which lack a Breech-
lock mount ring, with the exception
of the Macro lenses, are set for manual
diaphragm control as follows:
1. Before mounting the lens, insert the hole
of the accessory manual diaphragm adapt-
er over the tip of the automatic aperture
lever at th e rear of the lens. Push the
lever to U1e right and lower the
~dapter
into the groove to l ock the lever
m
that
position.
2.
MoLuH
Lht:
lens onto the accessory. The
diaphragm will now open and close as
the aperture ring is rotated.
When the manual diaphragm adapter is
attached on the rear o f one of these lenses,
never mount the lens directly on the camera
or directly on accessories designed for
automatic diaphragm control, such as the
Auto Bellows o r Bellows FL.