Nikon 1666 Instruction Manual - Page 52

Glossary (Continued) F Full-aperture metering One of the light-metering systems of a camera with a built-in TTL exposure meter. After you make the aperture setting, the camera determines the correct shutter speed by measuring the light with full aperture. As the aperture is kept fully open, the view in the viewfinder is bright, enabling easy focusing. The lens will then be stopped down to your aperture setting when you release the shutter. On the contrary, metering the light with the actual aperture setting for shooting is called "stop-down metering." This may darken the view in the viewfinder making focusing difficult. With some special lenses or certain accessories (such as a bellows attachment), only stop-down metering is available. G Guide number Used as a standard value to numerically show the illumination level (ISO 100, m, 20°C / 68°F) of flash. The value is indicated in units of GN (ISO 100, m). An aperture setting value for the correct exposure can be obtained by the following equation. Aperture value (f) = Guide number (GN) / Shooting distance (meters). I ISO film speed A unit to indicate the film sensitivity, defined by the ISO (International Organization for Standardization). M Manual exposure Shooting is performed by manually setting the shutter speed and aperture value based on the light level measured by an external or built-in exposure meter. With manual exposure, shooting can be performed independent from changes in conditions. You may want to make a solemn image by setting the exposure to a low level, or add a cheerful atmosphere by setting it to a high level. Mechanical shutter A shutter system that mechanically controls the shutter speed. Its advantage is that no power is required, permitting you to shoot even when the battery power is exhausted. This may be especially effective for photographing with long-time exposure or at low temperatures at which batteries would have to be warmed. Multiple-exposure photography To expose a single frame more than once. N ND filter ND stands for Neutral Density. ND filters can flatly decrease the light level without masking out any specific wavelength (color). O Overexposure A state in which the total exposure is too great when compared with standard exposure. 52