Canon T 90 - Manual (Page 150)

2) While pressing both.selectors, turn the
electronic input dial to the desired number of
exposures (for example, set "3" on the frame
counter if you want to make three exposures
on the same frame.)
3) Remove your fingers from both selectors.
• While shooting, the “ C§ ” mark will flash
on and off to warn you that the camera is
in the multiple exposure status
• Each time the shutter is released, the
preset number of exposures on the frame
counter will decrement by 1
When the preset number of exposures
have been completed, the film is automati­
cally wound to the next frame and the
multiple exposure status is automatically
cleared.