Movie Makers (Jan-Dec 1949)

369 PLYWOOD HOLDER GLASS REFLECTOR HEAVY CARD BOARD OR VIEWFINOER TRIPOD BASE OR HOLDER PLYWOOD MASK FRAME HOLDER A GUIDE DIA. BRASS RODS SUPPORT BRACKET SET SCREWS ' BOTH SIDES COMPLETE MASK BOX ASSEMBLY is seen above. Mask holder unit in front serves also as fine filter mount, while built-in viewfinder on microscope slide glass is author's own valuable addition to standard design. Assorted masks are seen at right. Yours for the masking are all the effects of split screen multiple exposure with this homemade matte box a mask box mounted out front does look impressive. There are, of course, a few excellent models of this gadget now being offered commercially. You'll probably see them advertised in this magazine. But I happen to be one of those filmers who get fun from making their own accessories as well as from making movies. The mask box outlined on these pages embodies all of the standard features of this unit — with one or two additions of my own design. SIMPLE TO MAKE The construction is basically quite simple and it may be modified still further to suit your own ideas. As an example, the bellows from an old camera might well be substituted in place of the heavy cardboard shown. Or, again, the viewer on the side might be eliminated if you do not need it. There are many variations and alterations that may be made to suit the individual. The materials required are very simple and the box is easily fabricated. It consists basically of a lighttight box or bellows, suitable end pieces, three brass rods, two supporting brackets, two flanges and a holder that fits on the tripod. I began by first making the box out of heavy cardboard, the type such as is used for mounting photographs. Four pieces of cardboard were cut to fit the end pieces, then painted a dull black inside and out. They were fastened together with airplane glue and masking tape, as were the other parts. BUILT-IN VIEWFINDER Before assembling the four pieces I cut a hole out of one and inserted a tube to be used as a viewfinder. A piece of slide glass from a microscope was then placed at a 45 degree angle with the hole and glued into place. In use, the tube provides for correct centering visually and is an aid in correcting parallax. Your pictures, of course, are taken through the glass; but care should be used in select ing optically perfect glass and in keeping it clean. A piece cut from a photographic glass plate is as good as the microscope slide. A machine shop made the flanges, support brackets and tripod holder (Figs. 1, 2 and 3). These were made of brass, but here again some lighter material such as aluminum could have been used. FITTED TO CAMERA The front and back boards, or end pieces (Fig. 4), were made of % inch plywood which gives good rigidity. The hole in the smaller end piece should be drilled slightly larger than the diameter of the lens with which it will be used. If you have several different lenses, you should provide an end piece to fit each one. On the front piece, strips of plywood were securely fastened as shown, to be used as guides and a stop for the masks. The supporting rods were made of Vi inch brass. The mask box supports were threaded ^4-20 and are securely screwed into the flanges which are shown in Fig. 2. The flanges were in turn fastened to each end piece by small screws. The tripod holder (Fig. 1) was made to fit on the top of my particular tripod, but it may be adapted for any other make. The 9/32 inch diameter hole allows room for the tripod screw to pass through, thereby fastening the camera and supporting the box. The support brackets have offset holes for the brass rods with an "X" dimension shown in Fig. 3. This "X" dimension will vary with different cameras because of the difference between the position of the tripod socket hole and the center line of the lens. The bottom rod is parallel to the socket hole, whereas the upright rods are parallel to the axis of the lens. These support brackets afford both lateral and vertical adjustment, making it possible to attain a high degree of accuracy. [Continued on page 385]