Chapter 5 of "Instruction Manual for RB Super Graflex &c"

Rising Front and Drop-Bed

In some instances, you may find it necessary or helpful to raise the lens slightly to bring the subject into better position on the ground glass, or to prevent tilting the camera up and causing the convergence of vertical parallel lines when photographing a high building. This is accomplished by loosening the riming-front knobs on each side of the front standard, shifting it vertically, and locking it in the new position by the rising-front knobs. (See Figure 10.)

The drop-bed similarly takes the place of pointing the camera down in photographing objects below the level of the camera. To drop the bed, rack out the track until it is entirely on the front bed and then depress the side braces; this frees the bed so that it falls into the dropped position. (This will be useful principally for "table top" set-ups or with long focal-length lenses).

Double-Extension Bellows (for Close-up Photography)

Figure 10
When using the camera for close-up photography, the lens is placed at a greater distance than normal from the focal plane (film position). (See page 7). This will necessitate a change in the exposure, since the f/ values engraved on the lens are based on a relationship existing only when the lens is at the infinity position. For close-up photography, we recommend that your exposures be determined in accordance with the following table. The lens-to-film distance bellows draw) can be determined approximately by measuring from the diaphragm-control ring of the lens back to the plane occupied by the film (the ground glass).
Reproduction Ratio Bellows
(Image size to Object size)
Bellows Draw Exposure Factor
1:8 1.125 f 1.265*
1:4 1.25 f 1.56*
1:2 1.5 f 2.25*
1:1.5 1.75 f 3.06*
1:1 2 f 4*
f=focal length

For black-and-white photography with standard films, you may find that the latitude of the film will compensate for much of the change in exposure so that no allowance for extension will be required unless copying larger than half-size (1:2). However, for color photography, we would recommend that you follow this table very closely because of the limited latitude of color materials.

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