Teleconverter

A device, used to increase the effective focal length of a lens that consists of optical glass. It is mounted between the camera and the lens and usually comes in two different sizes: 1.4X and 2.0X. A 1.4X teleconverter increases focal length by 1.4 times, while a 2.0X increases focal length by 2.0 times. The aperture of the lens is also increased by the same amount as the focal length is increased. For example, a 2.0X teleconverter increases focal length of a 200mm lens to 400mm; however, the aperture of F/2.8 is decreased to F/5.6.

Telephoto Lens

A lens with a long focal length - longer than the diagonal of the film format used.

Thumbnail

A small version of a digitized image. Image browsers and image editors commonly display thumbnails of several photos at a time. In Windows XP’s My Pictures, one can view thumbnails of photos in both the Thumbnails and Filmstrip view modes.

TIFF

Tagged Image File Format. An uncompressed non loosy image format.

Tone

In photography, usually refers to the gray values in an image.

Transparency

A processed and stabilized positive film image, i.e., a slide is a transparency.

TTL "Through the Lens."

Refers to flash or exposure metering which is read "through the lens," at the film plane.

Tungsten

A metal filament used in most light bulbs. Makes a reddish/yellow colored light. There are special films and filters for correcting the color cast from this light.

Tungsten Type Film

A color film that is color balanced to work under tungsten lighting. To use a tungsten type film type under daylight or flash, a color temperature conversion filter is needed. This film is also known as Type B film.

Type A Film

Color film that is color balanced for scenes illuminated by artificial light sources at a color temperature of 3400K - typically flood lamps.

Type B Film

Color film that is color balanced for scenes illuminated by artificial light sources at a color temperature of 3200K, typically tungsten and household lamps. This is the more commonly used of the two types: A and B.