BELLOWS: Bellows are accordion-folded segments between the lens and the
film plane of most process and copy cameras. Bellows maintain light-tight
integrity during enlargements and reductions. The use of bellows on small
adjustable cameras is limited to macro (close up) or copy work.
EXPOSURE CONTROLS: Exposure controls involve shutter speed dials
and aperture rings. Once the copy plane, lens plane, and film plane are
correctly positioned, select the settings for exposing film to the light. The
length of exposure is called shutter speed. The amount of exposure is called
aperture. Automated cameras may set shutter speed, aperture, or both for
you. Cameras that require you to select the aperture and automatically set
the corresponding shutter speed are called aperture priority. Cameras that
automatically select apertures based on your shutter speed-selection are called
shutter priority. The shutter speed dial is located on the head of the camera.
The aperture ring is a collar around the lens. Most cameras allow manual
manipulation or override of the automatic mode.
FILM SPEED: Film speed indicates how sensitive or receptive film is to
light. Every film type has a rated speed set by the International Standards
Organization (ISO). The film speed is referred to as ISO. Set the camera
film speed dial to reflect the ISO of the film. Generally, the lower the ISO
rating, the slower the film records light. A slow film requires more light and
either longer shutter speeds or larger aperture openings to acheive proper
film exposure. Slow film has a less grainy appearance in print, which results
in increased resolution or sharpness in enlargements.