camera assembly 14 slidably mounted on a column not shown for vertical movement in a well known manner in order to vary reduction ratio an original document 11 on a stationary table 10 is placed in the field of view of the camera lens 24 and uniformly illuminated by illumination lamps 12 12 at the upper right and left of the table 10 the illumination light from the lamps 12 12 illuminates the document 11 and is reflected thereby the reflected light is focused on a photographic film 15 by means of the objective taking lens 24 to create a latent image of the document 11 under the control of a shutter 23 in the camera assembly 14 there are reels 16 17 detachably mounted for film supplying the winding respectively the film 15 is withdrawn out from the film supply reel 16 and is wound up on the film winding reel 17 via guide rollers 18 25 at an exposure position the film 15 is held flat between an exposure mask 21 with an opening 32 for defining an exposure aperture and a pressure plate 20 forced against the film and thence against the exposure mask 21 by the force of a compression spring 19 this exposure mask 21 which is the one selected in accordance with an intended microfilming format from several types of exposure masks.