Bright spots of light, often taking the shape of the aperture, which appear in the camera viewfinder or in the final photograph when a lens is pointed at a bright light like the sun; controllable through the use of multilayer coating of the lens elements.
GN (Guide number)
Used to express the power output of the flash nit. It indicates the power of a flash in relation to ISO film speed. Guide numbers are quoted in either meters or feet. Guide numbers are used to calculate the f/stop for correct exposure as follows: Number calculated by multiplying proper flash exposure aperture by the subject distance.
GPD
Gallium Photo Diode. Metering cells for measuring exposure, using gallium arsenide-phosphide, just like SPD or Cds cells.
Grain.
Minute metallic silver deposit, forming in quantity the photographic image. The individual grain is never visible, even in an enlargement, but the random nature of their distribution in the emulsion causes over-lapping, or clumping, which can lead to graininess in the final image. Also cross check with below for graininess.
Graininess
The sand-like or granular appearance of a negative, print, or slide. Graininess becomes more pronounced with faster film and the degree of enlargement.
Grey card (18% Grey Card).
Tone used as representative of mid-tone of average subject. The standard grey card reflects 18 per cent of the light falling on it.
Halation.
The production of "halos" round bright spots in an image, by light reflecting from the back of the film-base. General film bases are given a light absorbing coat the anti-halation back to prevent this.
Hi 8
Video recording format, also refer a High Band 8mm format.
"H"-Format
One of the three selectable Advanced Photo System print formats; identical to the 9:16 aspect ratio used in high-definition television (HDTV); suitable for wider shots than usual, such as groups; produces prints of 3.5 x 6 inches or 4 x 7 inches
High Contrast
A wide range of density in a print or negative.
Highlights
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.
Hot Shoe
Usually rest around the pentaprism of the camera (but some were designed around the film rewind knob). It has an electrical contact which mated with a contact in the mounting foot of the flash unit. This allows the camera to fire the flash at the proper time without any other electrical connections between flash and camera.The fitting on a camera that holds a small portable flash. It has an electrical contact that aligns with the contact on the flash unit's "foot" and fires the flash when you press the shutter release. This direct flash-to-camera contact eliminates the need for a PC cord. Some referred it as accessory shoe. Modern flash demand more than just the main electrical contact and often has more dedicated functions such as TTL control, viewfinder ready light etc.and thus, you will find more secondary contacts other than the main.
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.
Hyperfocal Distance
Distance of the nearest object in a scene that is acceptably sharp when the lens is focused on infinity.
Image.
Two-dimensional reproduction of a subject formed by a lens. When formed on a surface, i.e. a ground-glass screen, it is a real image; if in space, i.e. when the screen is removed, it is an aerial image. The image seen through a telescope optical viewfinder, etc. cannot be focused on a surface without the aid of another optical system and is a virtual image.
Incident light.
Light falling on a surface as opposed to the light reflected by it.
Infinity.
Infinite distance. In practice, a distance so great that any object at that distance will be reproduced sharply if the lens is set at its infinity position, i.e. one focal length from the film.
Interspersed Aspect Ratio
A basic requirement of certified photofinishers and certified photofinishing equipment; specifies the three system print formats - C, H and P - that users select during picture-taking must be available at photofinishing.
Interchangeable lens.
Lens designed to be readily attached to and detached from a camera.
Inverted telephoto lens.
Lens constructed so that the back focus (distance from rear of lens to film) is greater than the focal length of the lens. This construction allows room for mirror movement when short focus lenses are fitted to SLR cameras.
Iris.
Strictly, iris diaphragm. Device consisting of thin overlapping metal leaves pivoting outwards to form a circular opening of variable size to control light transmission through a lens.
ISO Speed
The international standard for representing film sensitivity. The emulsion speed (sensitivity) of the film as determined by the standards of the International Standards Organization. In these standards, both arithmetic (ASA) and logarithmic (DIN) speed values are expressed in a single ISO term. For example, a film with a speed of ISO 100/21° would have a speed of ASA 100 or 21 DIN. The higher the number, the greater the sensitivity, and vice versa. A film speed of ISO 200 is twice as sensitive as ISO 100, and half that of ISO 400 film.
IX Information Exchange
The ability of Advanced Photo System film to communicate with devices, and devices to communicate with film; can be accomplished optically or magnetically using a thin magnetic layer on the film that records digital data.
JCII
Japan Camera Inspection and Testing Institute. Organisation in Japan to monitor export quality of Japanese made cameras, in 1992, may be because of the global localisation programs, most lower end and some mid-range cameras are made and produced in countries outside Japan and their duty is relieved.
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