NSL Photography's™ Glossary of Photographic Terms - H

Choose your Glossary page by letter:
# A B C D E F G H I J K L M

HDR (High Dynamic Range Imaging)
In image processing, and digital photography, high dynamic range imaging (HDRI or just HDR) is a set of techniques that allows a greater dynamic range of luminances between light and dark areas of a scene than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows. The technique is used when the range of exposure of an image is beyond the capability of the camera's sensor to record it in a single image.

High Contrast
A wide range of density in a print, image or negative.

Small, very bright part of image or object. Highlights should generally be pure white, although the term is sometimes used to describe the lightest tones of a picture, which, in that case, may need to contain some detail.

A graphic representation of the range of tones from dark to light in a photograph. Many digital cameras, especially DSLRs, include a histogram feature which displays the histogram on the screen of the camera which enables the photographer to check on the exposure of the photo immediately after it is taken.

Hot Shoe
Usually attachment socket and holder above the viewfinder of an SLR or DSLR (but some were designed around the film rewind knob of film cameras). It has an electrical contacts which mate with contacts in the mounting foot of flash units which are inserted in the hot shoe. This allows the camera to fire the flash at the proper time without any other electrical connections between flash and camera.

Handle Mount flash
Also often referred as bracket flash. It comprised of one arm of the L-shaped bracket extends under the camera body and uses the camera's tripod socket to mount the camera on the bracket. The vertical arm of the bracket serves as a handle and mounts a flash unit in an accessory shoe often on top of the handle portion, but there are other methods. Flash mounted in a bracket usually requires a separate electrical cord to make the electrical connection between camera body and flash unit.

When an auto-focus system has trouble finding the focus in a low contrast image or in poor light, the lens moves continuously from close-up to infinity looking for the correct point of focus.

Hyperfocal Distance
Distance of the nearest object in a scene that is acceptably sharp when the lens is focused on infinity.

If you have any suggested additions or corrections to the Glossary, please contact us.