Falling Plate Camera
The other configuration of multiple-negative camera I've built is the "Falling Plate" design, of which I've built three versions. Here are some details on one of these models:
Front view:
Detail of shutter mechanism, shown open. The lower aluminum sleeve that contains the sliding shutter is epoxied to the front of the camera using JB Weld epoxy. The upper brass support for the shutter pull rod is attached using machine screws. The shutter pull knob -- an acorn nut -- is also the top front viewing dot:
Rear view of camera, access lid closed and attached via thumb screws. The black tape on the corners of the rear lid are pieces of gaffer's tape. They've been attached because the sheet of aluminum forming the lid are delaminating from the inner wooden frame of the lid. The entire camera's aluminum skin is JB Welded to the inner wooden space frame, but in the case of the lid it is coming loose in places. In the future, perhaps an inner frame made from square brass tubes (they can be soldered together) instead of wood, and an outer skin made from either sheet brass or galvanized steel (either of which can be soldered, instead of glued) :
Inside view. The camera is constructed around a space frame made from 1/4" thick square hardwood sticks. The thickness of the frame permits mechanisms, like the sliding film changing pin's light trap, to be built into the walls of the camera. Also notice the two parallel sticks in the middle bottom of the floor of the camera; they were intended to hold the tripod nut, but the flexibility of the sheet metal skin caused the whole camera to be very wiggly upon the tripod. Hence the reason why I've since bolted the floor of the camera securely to the beefy wooden tilting support base. Screws securing the camera to the base can be seen in the bottom corners:
Film changing knob. Of course, you can't see the interior light trap mechanism permitting the knob to be slit back and forth; it's really just a 1/8" model plywood plate, sliding inside the 1/4" thickness of the walls of the box (inside a light-tight enclosure with slots for the screws to protrude), with a 6/32 machine screw penetrating from the outer knob to the inner pin:
The ledge upon which the film plates sit; and the front lip (about 1/4" high) which prevents the front plate from prematurely falling off and jamming the mechanism. The distance between the top edge of the film plates and the ceiling of the camera needs to be less than this 1/4" high lip, to that when the camera is jiggled the front film plate won't jump over the lip and jam the works:
Demonstration of a fallen film plate. The camera is tilted forward ~ 45 degrees, then the changing knob is slid sideways. This camera's plates fall so quietly that you really need to listen carefully to hear them fall. Then upright the camera and slightly jiggle it back and forth, to ensure the fallen plate sits securely in the bottom of the camera.
You can also imagine that if the film plate doesn't fall properly, or if the camera is subsequently upended or severely manhandled, the fallen plates can become upset and block the view of the pinhole.
It may not be entirely obvious, but the notches in the top of the plates # 1-8 alternate right, left, right, left, etc. So the changing knob is alternately slid right and then back left to drop subsequent plates. There's space for more than 8 plates, BTW, but I haven't made more:
Some details of the bottom support plate, an addition to this camera's original design. As indicated earlier, the bottom skin of the camera flexes too much to permit a secure mount atop a tripod, especially in the wind, hence the addition of this bulky 3/4" thick plywood double-plate hinging support.
This was originally intended to be used with my homemade tripods, which have a cable loop on the legs permitting the head to be levelled with the horizon, but lacked the ability to tilt the camera. Since most landscape images require the camera to be tilted downward, the mounting plate hinges from the front. A regular brass door hinge is used (see front view of camera, first image in this series.)
The perforated aluminum strips provide for a variable tilt position, using thumb screws.
The additional viewing dots, just markings with ink, were provided when I enlarged the original 5"X8" format to 6"x9.5". These viewing dots are surprisingly accurate in framing one's perspective:
The camera remains very functional, despite several years of severe abuse out in the badlands of New Mexico.
Here's an example, taken atop the Sandstone Overlook in the El Malpais National Monument in western New Mexico. Preflashed grade 2 paper negative:
~Joe
Therefore the viewing window looks into a narrow square tunnel whose inside end rubs up against the paper backing strip, ensuring no light leaks around to the front side to fog the photo paper.
