Black and White photography
Crime scene photography
Fashion and glamor photography
Fine Art photography
Cameras, Continued Camera Cameras consist of seven basic components on three parallel planes. components Misadjustment of any component part of a process camera affects the reproduced image in size, clarity, or density. The three parallel planes of a copy camera are the copy plane, the lens plane, and the focal plane. Consult the manufacturer’s operating instructions for precise operator adjustments.
COPY PLANE: The copy plane is a glass copyboard that holds the original copy in place. The most common size is 18 by 24 inches with gridded reference lines to help align the original copy. Vacuum pressure creates suction to flatten the copy during a shoot. The copy plane may move on a track for proportional reductions or enlargements.
LENS PLANE: The lens plane holds the lens in position. Some lens planes have interchangeable lenses. The lens plane moves along a track for proportional reductions or enlargements.
FILM or FOCAL PLANE: The film plane holds the film in place in the back of the camera. The film plane may also have a filter attachment for halftone or color separation work. Without film, the ground glass of the focal plane allows for fine focusing an image.
SCALES: Most cameras reduce to 50 percent and enlarge to 300 percent or a range in between.
FOCUSING CONTROL: Handwheels or cranks rotate to focus an image. Newer machines have automated push-button focusing.
BELLOWS: Bellows are the accordion folded segment between the lens and the film plane. Bellows maintain lighttight integrity during enlargements and reductions.
EXPOSURE CONTROL: Once the copy plane, lens plane, and focal plane are positioned correctly, the camera scales recommend settings for the f/stops and/or the shutter speed. Some cameras are set manually and other cameras are automated. Automated cameras are aperture priority cameras where the operator sets the shutter speed and the camera sets the aperture opening. Shutter priority is when the operator sets the shutter speed and the camera selects the aperture. Little figuring is done by the operator in either case.
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of great importance for the appearance at the image plane. If the admitted rays also pass through a lens, highly collimated rays (narrow aperture) will result in sharpness at the image plane, while uncollimated rays (wide aperture) will result in sharpness for rays with the right focal length only. This means that a wide aperture results in an image that is sharp around what the lens is focusing on and blurred otherwise. The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image).
An optical system typically has many openings, or structures that limit the ray bundles (ray bundles are also known as pencils of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that determines the ray cone angle, or equivalently the brightness, at an image point.
In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope the aperture stop is typically the edges of the objective lens or mirror (or of the mount that holds it). One then speaks of a telescope as having, for example, a 100 centimeter aperture. Note that the aperture stop is not necessarily the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a relatively large stop to be the aperture stop for the system.
Sometimes stops and diaphragms are called apertures, even when they are not the aperture stop of the system.
The word aperture is also used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy for example, a photometric aperture around a star usually corresponds to a circular window around the image of a star within which the light intensity is summed.
A camera is a device that records images, either as a still photograph or as moving images known as videos or movies. The term comes from the camera obscura (Latin for "dark chamber"), an early mechanism of projecting images where an entire room functioned as a real-time imaging system; the modern camera evolved from the camera obscura.
Cameras may work with the light of the visible spectrum or with other portions of the electromagnetic spectrum. A camera generally consists of an enclosed hollow with an opening (aperture) at one end for light to enter, and a recording or viewing surface for capturing the light at the other end. A majority of cameras have a lens positioned in front of the camera's opening to gather the incoming light and focus all or part of the image on the recording surface. Most 20th century cameras used Photographic film as a recording surface, while modern ones use an electronic camera sensor. The diameter of the aperture is often controlled by a diaphragm mechanism, but some cameras have a fixed-size aperture.
A typical still camera takes one photo each time the user presses the shutter button. A typical movie camera continuously takes 24 film frames per second as long as the user holds down the shutter button, or until the shutter button is pressed a second time.
Slow shutter speeds are often used in low light conditions, extending the time until the shutter closes, and increasing the amount of light gathered. This basic principle of photography, the exposure, is used in film and digital cameras, the image sensor effectively acting like film when exposed by the shutter.
Shutter speed, or more literally exposure time, is measured in seconds, but often marked in reciprocal seconds. A typical exposure time for photographs taken in sunlight is 1/125th of a second, typically marked as 125 on a shutter speed setting dial. In addition to its effect on exposure, shutter speed changes the way movement appears in the picture. Very short shutter speeds are used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for artistic effect.
Adjustment to the aperture controls the depth of field, the distance range over which objects are acceptably sharp; such adjustments generally need to be compensated by changes in the shutter speed.
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. Relatively insensitive film, with a correspondingly lower speed index requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a slow film. Highly sensitive films are correspondingly termed fast films. A closely related ISO system is used to measure the sensitivity of digital imaging systems. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). Basically, the higher the film speed, the worse the photo quality.
In this metering mode the camera will use the light information coming from the entire scene and averages for the final exposure setting, giving no weighting to any particular portion of the metered area.