Polaroid 636 Repair Manual page 15

13. After the blades close, the motor is turned on. The timing gear advances the pick, indexes
the counter, and brings the S5 actuator back to its original position. The shutter system
is latched closed, ending the low ambient NEAR sequence.
14. If the light measured 2 milliseconds after the flash has fired is less than 50% of the total
needed for a proper exposure, the camera decides the subject is FAR.
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