directly over the aperture 22 the film f is exposed to the light emitted from the light sources 5 for illuminating the document s on the original board 2 reflected by the document s and entering the camera head 7 through the shutter in an open position and the aperture 22 the lens 21 determines a photographing magnification in this embodiment the photographing magnification is variable by operating a magnification switching mechanism shown in fig1 to move the lens 21 toward or away from the film f the magnification switching mechanism of fig1 comprises a focusing helicoid 12 including an outer cylindrical element and an inner cylindrical element the outer element is rotatable to move the inner element in directions perpendicular to the document s the lens 21 is mounted in the inner element number 121 indicates a latching solenoid connected to the focusing helicoid 120 through a connecting lever 122 and a plunger 123 movable right and left in the drawing the solenoid 121 when electrified drives the plunger 123 to rotate the focusing helicoid 120 a predetermined angle u03b8 which moves the lens 21 along an optical axis thereby varying the photographing magnification the latching solenoid 121 may be electrified only when varying the photographing magnification after power is cut off upon completion of the switching operation the latching solenoid 121 remains in the position it assumes with the electrification the latching solenoid 121 may be the three position stabilizing type instead of two in which case the photographing magnification is variable in three steps the device for defining the aperture 22 includes a movable plate 24 for defining an end of the aperture 22 opposed to an unexposed side of the film f which is adjacent the supply reel 23 and a stationary plate 26 defining the.