V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 308
Obviously, not everything you photograph is middle gray.
Snow, for example, is obviously brighter (near 100%
reflectance), and coal in an unlit underground mine is
dramatically darker. As Nikon notes in some of their manuals:
you normally use a positive correction value (e.g. +0.7 stops)
when your subject is darker than the background, and you
use a negative correction value (e.g. -0.7 stops) when your
subject is brighter than the background. Put another way:
without exposure compensation, large expanses of white
snow or black coal would both appear gray in your photos.
That’s because the meter thinks the world is middle gray and
tries to match everything to that value.
Object
Meter Sees it As Result
Solution
Bright white,
such as snow
Brighter than
middle gray
Camera
underexposes
ADD
exposure (+
exposure
compensation)
Mid-tone
values, such as
grass or plants
Same as middle
gray
Camera exposes
correctly
--
Very dark
object, such as
black lava rock
Darker than middle
gray
Camera
overexposes
SUBTRACT
exposure (-
exposure
compensation)
Virtually every professional I’ve met has his or her own
method of deciding when to override the camera’s meter, but
every pro I know also does so with regularity
92
. Fortunately,
it’s quite simple to do, and Nikon has been good about
keeping the exposure compensation control in the same
location on most of their recent camera bodies, whether they
are film or digital
93
.
92
As you might expect, I have my own method of dealing with exposure. Since this
isn’t a book on photography basics, I won’t elaborate on it here other than to say that
with digital cameras you have all the luminance information you need to make
excellent exposure decisions using the histogram. See “How to Interpret Histograms”
on page <267> if you’d like more.
93
The N80 was an exception.
