Kodak DCS 300 Series User Manual page 242

Flexible Program
Temporarily shifts an automatically selected shutter speed/aperture combination
while maintaining correct exposure. That is, a desired shutter speed or aperture can
be selected with the camera in Programmed Auto Exposure mode.
Focus Tracking
Enables the camera to assess the speed of a moving subject according to perceived
focus data, then set correct focus settings by anticipating subject position--and
driving the lens to that position at the exact moment of exposure.
f-number
The numbers on the lens aperture ring and on the camera's LCD which indicate the
relative size of the lens aperture opening. The f-number series is a geometric
progression based on changes in the lens aperture opening as it opens and closes.
Going up the scale, each number is multiplied by a factor of 1.4. Each f-number on
the scale (except for the lowest) actually represents double the amount of light
transmitted through the lens using the f-number below it. The standard numbers for
calibration are 1.0, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, etc.
Front-Curtain Sync
The flash fires an instant after the front curtain of a focal plane shutter has finished
traveling across the imager plane with the Flash Sync mode at normal sync. (See
also Rear-Curtain Sync.)
Guide number
The guide number indicates flash power in relation to ISO speed. Guide numbers
are quoted in either meters or feet, and are used to calculate f/stop for correct
exposure as follows:
guide number
f/stop = ———————————
flash-to-subject distance
Using a selected aperture, the required flash-to-subject distance can be calculated
by using the formula:
flash-to-subject distance = ———————
Useful for determining the maximum flash-to-subject distance for flash
photography.
D-4
guide number
f/stop