Canon FTb Instructions Manual page 36

• Whenever a lens is removed, be sure to put on the dust
cap to protect the various signal levers and pins . When not
in use for a long time, protect the mirror with a flange cap .
Lens Signal
Aperture Signal Lever: Transmits the preset f/stop of
the automatic aperture to the camera body. It is on a 1 to
1 movement basis with the preset aperture through lever
manipulation. The aperture signal lever is operable only
when the bayonet mount ring is turned to the attachment
position.
Full Aperture Signal Pin: Transmits the full aperture
stop when a lens with a different full aperture number is
mounted. It also performs error compensation of the full
aperture metering.
Automatic/Manual Aperture Lever: Stops down the
aperture to the preset position. Clamp it to the right side
for manually operated aperture.
EE Lock Pin: This is a protective pin to prevent the
aperture of the lens from moving to the green mark un·
intentionally . In order to set at the green mark , turn the
aperture ring while pushing down the EE lock pin. When
withdrawing from the green mark , turn the aperture ring
again pushing down the EE lock pin .
EE Switch Pin: When the preset aperture ring is set at the
green mark for EE use, the lens can be attached only to the
Canon F·1. If the lens is attached to the FTb, it cannot be
set at the green mark.
Pin: Reserved .
36
Full Aperture Signal Pin
Automatic/ Manual
Aperture Lever