Heres 2 photos taken during a shutter test where the blade has been almost closed over and a very tiny slit is all that lets any light through.
This would produce a shutter speed too fast for effective exposures (in convnetional use anyways). The LED light source illuminating the paper on the other side of the gate flickers and this produces the strobed scans of the slit as a photo is taken with an iphone4.
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