121. Home-Made Camera Box

Home-Made Camera Box. The following applies to a 5x7 size instrument - either larger or smaller ones can be constructed on the same principles: The first requisite is the back of your ordinary camera. On practically all hand and view cameras it is possible to remove the ground-glass spring-back. If this back is reversible it will be perfectly square - i. c, the length of sides and ends are the same. Where the back is not reversible the sides will be longer than the ends. Take the measurements from the inside of the groove or flange of this back (which, if a reversible back, will be 7 1/2 inches) and cut a piece of board to this size, using half-inch lumber.

122. Next, construct a box 2 1/2 to 3 inches deep, omitting the ends, using quarter or half-inch material (the thinner the better), and for a 5x7 camera the sides of a cigar box will answer nicely. Care must be taken that the boards are free from cracks or holes, as the camera must be absolutely light-tight. The box should be constructed to fit snugly around the square board you have just cut (which latter is to be the front-board to which the lens is attached). The spring-actuated ground-glass back, which you have taken from your regular 5x7 camera, will also fit perfectly in the rear end of the box. Temporarily fasten this in position (it may be tied on with a cord). Now, in the center of the front-board cut a hole to receive the lens. For a 5 x 7 camera the diameter of the opening should be 2 3/4 inches on the front side, while the opening should be beveled so that the inside diameter will be at least 3 1/4 inches.

123. Having the ground-glass back in position in the box, lay it on a table and insert the front-board. Insert a ruler or similar measure in the opening of the front-board and allow the end to rest on the ground-glass, then move the front-board in or out until the front surface of it is the exact focal-length of the lens from the ground-glass. In other words, the distance between the front of the front-board and the ground-glass should be equal to the focal-length of the lens. In the case of the No. 000 lens, this distance is 2 3/8 inches.

Copyright l902, by C. C. Langill, N. Y.

Illustration No. 14

Park Row Building, New York

Made with Goerz Hypergon Lens

See Paragraph 119

Copyright, 1902, by C. C. Langill, N. Y. Illustration No. 15 Building on Broadway, New York Made with Goerz Hypergon Lens See Paragraph 119

124. Being careful that the front-board is on a perfectly parallel plane to the ground-glass, fasten it in position by inserting small brads in the sides of the box. Now, remove the back, and in order to be sure that all light is excluded insert putty all around the inside edge, between the front-board and the sides of the box; then, paint the whole inside with black paint. A small nut may be procured from a hardware store and this fastened in position in the bottom of the camera, the size of the nut being such as to fit the tripod screw; or a brass nut made to fit the regular tripod screw may be obtained from any camera manufacturer. The back of the camera may be tied on to the box with cord, but it would be far neater to make small brass spring catches to hold the back in position.

125. The outside of the camera can be carefully sandpapered and then either stained or varnished. A waterproof stain will be the best to use. By using a little ingenuity and working with care a very practical instrument can be easily constructed by anyone. Bear in mind that the lens is of universal focus, and that it is not necessary to focus - the distance from the lens to the ground-glass must be equal to the focal-length of the lens.

126. Making The Exposure

Making The Exposure. The star-diaphragm should be used during three-fourths of the exposure and removed altogether during the latter part of the exposure. The average exposure required for exterior views is from 3 to 6 seconds in ordinary sunlight - using the smallest-aperture. When an exposure of 6 seconds is required, the star-diaphragm should be kept in front of the lens for 4 seconds and then removed by lightly pressing down on the release lever, H. (See Illustration No. 13.) As the exposures will be of some length the cap can be used, and no shutter is required. The exact amount of exposure for all work, whether interior or exterior, can be ascertained by figuring out the f value. Bear in mind that the largest aperture of the Hypergon lens is f. 22, while the smallest one is f. 31, or U. S. 60.