Manual Aperture Control - Canon AT-1 Instructions Manual

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mirror, this stopped-down coupling lever
- 1
becomes visible, as does the red mark in the
case described above.
The Extension Tube FD 25 and FD 50
especially designed each for the FD 50mm
!
and FD 100mm macro lenses should be used
1
with full aperture metering. In this case, depth
of the field can be assured in the viewfinder
by pressing in the stopped-down lever.
Manual Diaphragm Control
When accessories requiring manual
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diaphragm control are used between the
camera body and
a
lens, lock the lens auto- --
-.
matic aperture lever in the manual position
before mounting the lens.
Lock for Manual Diaphragm Control (1
1
For manual diaphragm control, push the
automatic aperture lever counterclockwise
until
it
stops and locks. When accessories such
a s extension tubes are attached to a lens that
has been set for manual control, the dia-
phragm blades
of
the lens open or close
as
the
aperture ring is turned. To revert from manual
control, reset the automatic aperture lever to
i t s
original position.