NSL Photography's™ Glossary of Photographic Terms - T

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Tear Sheets
Tear sheets refer to ads taken out of the pages of magazines, newspapers and other printed matter. Any time work is published, the author gets copies, often literally clipped out of copies of the magazine, for their own future advertising and portfolio. Tear sheets provide evidence that the authors work has been published. Tear sheets are similar in this regard to reprints of articles.

Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.

A teleconverter is a secondary lens which is mounted between the camera and a photographic lens. Its job is to enlarge the image obtained by the original lens. Teleconverters are typically made in 1.4x, 1.7x, 2x and 3x models. The use of a 2x teleconverter gives the effect of using lens with twice the focal length. It also decreases the intensity of the light reaching the film by a factor of 4 (an equivalent of doubling the focal ratio) as well as the resolution (by a factor of 2).

Tear sheets got their name since it used to be common for magazines to rip up a few issues and send the pages torn out to authors, photographers, etc.

Telephoto Lens
In photography, a telephoto lens has a specific construction of a long focal length lens in which the physical length of the lens is shorter than the focal length. In these lenses the optical center lies outside of its physical construction, so that the entire lens assembly is between the optical center and the focal plane. A regular lens of a focal length that is longer than what is considered a normal lens is not necessarily a telephoto lens. A telephoto lens has to incorporate a special lens group known as a telephoto group, nevertheless, non-telephoto lenses of long focal length are often informally referred to as telephoto lenses. The angle of view created by a telephoto lens is the same as that created by an ordinary lens of the same specified focal length.

Telephoto and other long focal length lenses are best known for making distant objects appear magnified. This effect is similar to moving closer to the object, but is not the same, since perspective is a function solely of viewing location. Two images taken from the same location, one with a wide angle lens and the other with a telephoto lens, will show identical perspective, in that near and far objects appear the same relative size to each other. Comparing magnification by using a long lens to magnification by moving closer, however, the telephoto shot appears to compress the distance between objects due to the perspective from the more distant location.

Through the Lens (TTL)
Type of exposure meter built into the camera body and reading through the camera lens. May measure either at full aperture or at picture taking aperture.

Through the Lens Focusing
Viewing a scene to be photographed through the same lens that admits light to the film or sensor. Through the lens viewing, as in an SLR or DSLR camera, while focusing and composing a picture, eliminates parallax.

Through the Lens Metering
Meter built into the camera to determine exposure for the scene by reading light that passes through the lens. SLR and DSLR cameras have built-in meters which measure light after it has passed through the lens, a feature that enables exposure readings to be taken from the actual image about to be recorded, whatever the lens angle of view and regardless of whether a filter is used or not.

Time Exposure
A comparatively long exposure made in seconds or minutes.

Twin lens reflex camera that has separate viewing and actual exposure lenses.

Slide film.

A three-legged supporting stand used to hold the camera steady. Especially useful when using slow shutter speeds, macro and telephoto lenses.

Tungsten Light
Light from regular room lamps and ceiling fixtures, not fluorescent. Images produced under this light source can be extremely warm.

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