At that point, however, the contrast usually approaches the maximum that the film can accommodate. When the sky is dark, the moon's total luminance may be reasonably close to the values in Table 1. As the moon moves higher in the sky, a lighter rendering often better conveys the impression of the moon as a bright object. But it's largely a matter of personal taste. Moon luminance decreases rapidly as the moon moves away from direct opposition to the sun.
Atmospheric absorption is less at higher elevations, and the moon's luminance consequently greater.
Local atmospheric conditions can result in additional variations of as much as two exposure steps, even with a relatively clear sky. It's a good idea to start with the values in Table 1 and bracket several exposures on either side. A table of Exposure Values and equivalent camera settings is included in most camera manuals. The EV that will produce the correct exposure depends on the film speed and the subject luminance, so an EV for a given ISO film speed can also be interpreted as a measure of subject luminance. If the film speed is other than ISO 100, the EV must be adjusted accordingly.