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A lighting control that lets you fine tune the output of flash. This comes in useful when space is limited and you can't move lights back and forth or you want to adjust the exposure of one units when used in a set to balance the exposure.
A flash mode that's used to reduce the power of the output to quarter or half power. Some of the more advanced flashguns can reduce the output to 1/64 power which is useful for macro photography.
A calibration program that's used to ensure uniform colour appearance of digital images from input to output devices. Helps ensure that what you see on the monitor matches what you print out.
Indicates the output, or power, of an electronic flash. You can use the guide number to work out the aperture or flash to subject distance by dividing either into the guide number.
Indicates the energy content of the storage capacitors in an electronic flash. One Joule is the light output given by one watt burning for a second. Therefore a flash unit with a storage capacity of 300 Joules can supply the power to light a 300W lamp for one second. It doesn't take into account any electrical loss between the flash capacitor or flash tube, or the efficiency of tube and reflector.
A computer peripheral that’s used to output prints from digital images or data files. Most inexpensive printers are inkjet models that squirt out tiny jets of ink onto paper to make up the photograph. More expensive models tend to be either laser printer or dye-sublimation printers.
A device independent colour space used to create consistent color whatever the device used to create or output an image, such as a monitor, printer, computer, or scanner. It consists of a luminance value (L) and two chromatic values A from green to red and B from blue to yellow.
A useful feature that reduces the lamp output to make the image gradually become darker on screen. This prevents the viewer from sudden bursts of light or dark as slides are changed and gives a more pleasing transition from one slide to the next.
Flash units often have a range of settings that controls the amount of flash emitted. With portable on-camera flash this is normally controlled automatically by either the camera or a sensor on the flashgun. Studio flash are often less sophisticated and have a slider or switch offering half or quarter power. Some of the more expensive models can be adjusted more accurately though a greater range of stops.
The total number of pixels on a CCD array. This is not always the best indication of a camera's resolution as some CCD chips have a number of pixels around the that are only used to ensure the pixels that are used produce accurate colours. The true indication of a camera's resolution is the two figures quoted, say 1600x1200, which indicate the CCD's actual output. "A ... MP camera" is used to describe a model that has a CCD with a certain number times million pixels, which says something about how big the images are that it can create.