Inadequate range also
causes details to wash
out in light areas. Here,
overexposure is docu-
mented by a histogram in
which the columns crowd
the right edge. This photo is
overexposed by a seasoned
photographer who knows
that sometimes no single
exposure captures an
image successfully.(^4) After deliberately over-
exposing a shot by one
f-stop, the photographer
underexposes the same shot
by two f-stops. As expected,
the columns congregate on
the left end of the histogram
in the second shot. In this
variation, light areas are
properly exposed but the
same shadow detail that was
visible in the first photograph
recedes into the darkness.
5
In the digital darkroom,
the photographer combines
the two pictures to capture
details in both the light and
dark areas. Although
aesthetic judgments might
lead to photos that have a
predominately dark or sunny
cast, generally a photo looks
best—looksricher—if its
histogram consists of columns
distributed across the bed of
the graph. Some peaks and
valleys along the way are
perfectly acceptable. The
pattern to avoid is any
clumping or vacancy at
either end of the histogram
unless your subject is
primarily bright or dark.
6
Nature photography by Ed Knepley (www.knepley.net)
CHAPTER 5 HOW DIGITAL EXPOSURE SIFTS, MEASURES, AND SLICES LIGHT 83