Kodak DCS 700 - Manual (Page 255)

D-4
Guide number
The guide number indicates the power of a flash in relation to ISO. Guide numbers,
quoted in either meters or feet, are used to calculate the f/stop for correct exposure
as follows:
guide number
f/stop = ———————————
flash-to-subject distance
Using a selected aperture, we can calculate the required flash-to-subject distance
with the formula:
guide number
flash-to-subject distance = ———————
f/stop
Useful for determining the maximum flash-to-subject distance for flash
photography.
Histogram
The image histogram shows the range and distribution of tonal values for an image.
The tick marks at the bottom of the histogram represent photographic stops relative
to the factory-determined 18% gray level. The range of stops is from +3 to -7. The
double bar tick mark indicates the exposure value associated with 18% gray. Tick
marks to the right of the double mark indicate one-stop increments brighter than
18% gray, and tick marks to the left indicate one-stop increments darker than 18%
gray.
ISO
ISO is the international standard for representing film sensitivity. The higher the
number, the greater the sensitivity, and vice versa. For example, ISO 200 is twice
as sensitive as ISO 100, and half that of ISO 400. When you change the ISO setting
on your camera, you adjust the sensitivity of the imager equivalent to the
corresponding film sensitivity.
LCD
Liquid Crystal Display. Your camera has four: the Top Status LCD panel, Back
Status LCD panel, Image LCD panel, and the LCD inside the viewfinder.