c. If the subject is one that doesn't average out to a middle gray,
then you've got to use judgement. To understand why, you need to know one
thing about the intelligence of light meters; they haven't the slightest
idea what you are taking a picture of. In fact, light meters don't have the
slightest idea what a picture is. All they do is react to light, and the
calculator dial is designed to generate an exposure setting that will cause
the film, on average, to be 18 percent gray. If you point the meter at a
black cat, it doesn't know there is a black cat present - it just tells you
gray, then OK. Just remember that if you do this, then everything that is
lighter in tone than the black cat will be a lighter shade of gray or,
eventually, pure white. The same is true of a white house. The meter reads
the bright white house in sunshine and tells you what your camera setting
should be to make it look 18 percent gray. Once again, if that's what you
want, fine. But usually it isn't, so you must make adjustments, and that's
where the experience comes in.
d. Since you now know how the meter makes everything gray, then you
must decide how much lighter or darker you want your subject to really look,
example, a white house generally is about five times as bright as the gray a
meter wants to make it, so you would open your camera lens (or adjust your
shutter, or a combination of both) to give slightly over two stops more
exposure than the meter says you should. And that black cat is really about
three stops darker than the gray the meter would make it, so you should
adjust your actual exposure setting to give about three stops less than what
the dial tells you (fig 1-15).
You can take advantage of this in other
Reflected light reading technique
e. Kodak and other companies make a gray card which reflects 18 percent
of the light striking it, which is an average middle gray.
If you are
trying to take a picture of a very light or very dark scene that is not
average, place the gray card in the scene and take a close-up reflected
meter reading of it. Then you can use this exposure to make your picture.
Since the card is