when exposure counter shows the figure indicating the number of frames marked on the film packet 12,20 or36, the film has to be exchanged.
depress rewind release knob. knob remains locked in this position. swing out rewind crank on rewind knob. rotate rewind knob, not too quickly, in the direction of the engraved arrow. rewinding too quickly causes electrostatic charge and statics on the film.
towards the beginning of the film strip greater resistance becomes noticeable. after this, the crank turns more easily, a sign that the film is fully rewound. fold rewind crank down again.