PRINTING DEVICES

Printing the negative, or making a positive, is done by contact or projection. The contact printer is usually a box with an internal light source and a piece of glass that allows light to pass through it and the negative to form a latent image on photographic paper held in contact with the negative.

The projection printer allows the image on the negative to be projected and the size of the print varied. This type of printer consists of a light source, a negative holder and a lens and focusing device mounted on a frame which can be raised and lowered, depending on the size of the projected image desired. The photographic paper is held in an easel.

PHOTOGRAPHIC PAPER

Photographic paper has essentially the same emulsion as film. The chemical process is the same as that for film but produces a positive image. Choice of paper types is dependent upon the type of printing, surface, size and finish desired.

THE 35MM SINGLE-LENS REFLEX CAMERA

LEARNING OBJECTIVE: Identify the basic parts of a 35mm single-lens reflex camera.

As a Navy journalist, the 35mm single-lens reflex (SLR) camera (fig. 11-2) will serve as your tool to tell a story with photographs. For this reason it is important for you to become as familiar as possible with your camera, know what the camera can do, then know what you want it to do.

The SLR camera gets its name from the use of a mirror to reflect an image formed by a single viewing and taking lens onto a viewing screen for focusing. A

Figure 11-3. - A cutaway view of a 35mm SLR camera.

cutaway view of a 35mm SLR camera is shown in figure 11-3, and the basic principle of the SLR camera is shown in figure 11-4.

The mirror, set at a 45-degree angle to the optical axis, reflects the image through a pentaprism that accomplishes vertical and lateral correction of the image. At the moment of exposure, viewing is disrupted for a split second, as the spring-operated mirror swings out of the lens-to-film optical path. The mirror then automatically returns to its original position for the next exposure.

Important advantages of the SLR design are the ease of viewing and focusing and the photographer's ability to judge the effect of the depth of field at a selected aperture. Depth of field will be covered later in this chapter.

Probably the most important advantage of the SLR camera is the ease with which it can be used. Its small size and compactness enables photographers to carry them strapped around their neck or over their shoulder. Little preparation is necessary for them to be put into operation. Another advantage is the rapid film-changing devices incorporated into the cameras. They can be used to great advantage when many photographs must be made in a short period of time. Design of the average SLR camera is such that minimum time is required for making the settings and winding the film.

Because most SLR cameras make as many as 36 exposures on a single roll of 35mm film, the photographer can carry enough film in one pocket to make many exposures. This type of camera is helpful for news and action photography where several pictures must be made in a short time. It is also indispensable for color slide work.

Figure 11-4. - The basic principle of a 35mm SLR camera.

Modern SLR cameras accept a vast assortment of lenses, ranging from fisheye to extreme long-focus types. With their interchangeability of lenses, film backs and other accessories (such as electronic flash attachments), SLRs can more aptly be called camera "systems."

Lenses are usually attached to the camera by a bayonet flange. Focusing is done by turning the lens focusing ring. A screw thread, which runs around the inside of the lens barrel, moves the lens closer or farther away from the film, as the focusing ring is turned.

Most SLR camera lenses have an iris diaphragm. This diaphragm is held at full aperture for focusing and viewing and is stopped down automatically to the preset working aperture at the instant of exposure. This means that while the image on the viewing screen is bright and easy to see, only the connect amount of light reaches the film for exposure.

Your SLR camera will have a built-in exposure meter that usually reads "through the lens" (TTL). The meter may measure the light falling on the minor, the focusing screen, or in some models, even on the film at the instant of exposure. On an automatic camera, the meter even adjusts the aperture or shutter speed to give the correct exposure. On manual cameras the meter produces a display in the viewfinder to indicate the correct exposure. The user then sets the camera controls to get the correct exposure.

Almost all SLRs have final-plane shutters. They simplify the construction of the camera and make the use of interchangeable lenses easier. The shutter, aperture and mirror all work together in a precise sequence, repeated each time a picture is taken.

The relatively small size, ease and speed of operation, reliability and the high quality of photographs of the SLR cameras have combined to make it a favorite of professional photographers and photojournalists.