Nikon N6006 - Manual (Page 160)

Aperlure-pnofity auto: User selects aperture and camera
chooses shutter speed for correct exposure.
Manual: User select both shutter speed and aperture with the
meter’s recommendations for correct exposure.
Fill-flash
A method of flash photography which combines flash illumina­
tion and ambient light, but does not necessarily attempt to
balance the two types of illumination.
Flash synchronization
The flash is limed to fire coincident with the operation of the
camera’s shutter. There are two types of synchronization:
Normal Sync which fires the flash at the start of the exposure,
and Rear Sync which fires the flash at the end of the exposure.
f-number
Number which indicates brightness of film plane image. In-
aeasing/deaeasing f-number is opening/stopping down lens
aperture. The f-number series is equivalent to 1.4,2,2.8, 4,5.6,
8,11,16, 22, 32, etc. Changing one step to the next larger
number (i.e., from f/11 to f/16) decreases image brightness by
1/2; moving to nearest lower number doubles the brightness.
Guide number
The number given to a flash bulb or electronic flash unit to
indicate its power. A guide number may be quoted in meters
or feet, and depends on the speed of the film being used.
Guide numbers quoted assuming a relatively efficient reflector
surrounds the flash source, e.g., an average-sized room.
100