A ring, located on the outside of the lens usually behind the focusing ring, which is linked mechanically to the diaphragm to control the size of the aperture; it is engraved with a set of numbers called f-numbers or f- stops. Artificial light:

A metering feature that automatically recognises a subject in back lighting condition and increase the exposure to compensate. Accessory Shoes: - also often called "Hot Shoes "

Failing in the ability of a lens to produce a true image. There are many forms of aberration and the lens designer can often correct some only by allowing others to remain. Generally, the more expensive the lens, the less its aberrations (More attention to optical quality). While no single lens is called a 'perfect lens'. The "id [..]

This optical defect causes points on an object plane perpendicular to the lens axis to focus on a curved surface rather than a plane. c) Astigmatism

This optical defect causes the image of an off-axis point of light to appear as a comet-shaped blur of light. Coma, as well as curvature of field and astigmatism, degenerate the image forming ability of the lens at the rims of the picture. e) Distortion

A camera with manually adjustable settings for distance, lens openings, and shutter speeds. Most modern cameras including many compacts now have these functions. Adjustable-Focus Lens:

A standard developed by Kodak and four other System Developing Companies - Canon, Fuji, Minolta and Nikon - based on a new film format and innovativefilm, camera and photofinishing technologies. Generally, APS cameras are more compact in size and weight. There are options in various sizes of print out and it will even provide a thumbnail prints (Co [..]

Auto exposure Lock. Metering feature that used to hold the exposure setting when used in the automatic mode. Used most commonly in situation where off centering composition of the subject is desired and to retain the exposure setting of the subject OR where the level of exposure reading both the subject of interest and the background exposure readi [..]

The area of a scene that a lens covers or sees. Angle of view is determined by the focal length of the lens. A wide-angle lens (short-focal-length) includes more of the scene-a wider angle of view-than a normal (normal-focal-length) or telephoto (long-focal-length) lens. It can also be explained as the extent of the view taken in by a lens. It vari [..]

Lens opening. The hole or opening formed by the metal leaf diaphragm inside the lens or the opening in a camera lens through which light passes to expose the film. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f- numbers-the larger the number, the smaller the lens opening. Aperture affects depth of field [..]