V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 337
•
Contrast
—Contrast refers to the range of tonal values in
an image and how they’re compressed or expanded. A
“low contrast” image would have a narrow range of tonal
values (narrow histogram) while a “high contrast” image
would have a wide range of tonal values (wide histogram,
perhaps even exceeding the histogram’s width in really
high contrast situations). We use the
Contrast
control to
try to balance the range of data captured with the
available bit values (from 0,0,0 to 255,255,255). Picture
Controls allow you to set this to
A
(automatic), and levels
from
-3
(less contrast) to
+3
(more contrast).
•
Brightness
—Brightness is a bit of misnomer. You might
expect that such a control would simply move all data
values upward (to the right on the histogram). What you’re
actually controlling with this control is the image gamma
(mid-tone adjustment). Picture Controls allow you to set
this to levels from
-1
(lower gamma) to
+1
(higher gamma)
•
Saturation
—Saturation refers to what the camera does
with individual colors, boosting or reducing the apparent
color. We use the
Saturation
control to try to provide
visually appealing colors. For instance, for a low contrast,
low color scene, you might boost
Saturation
to provide
more visual interest. Picture Controls allow you to set this
to
A
(automatic), and levels from
-3
(reduced saturation)
to
+3
(increased saturation).
•
Hue
—Hue refers to where colors are on the color wheel.
Normally, red is red and blue is blue and green is green,
but we can push these colors around the color wheel
towards other colors (I’ll describe that more in the
individual section on Hue coming up). We use the
Hue
control to try to push colors towards a different rendering,
often to deal with color tainting in the light or subject
we’re photographing. Picture Controls allow you to set
this to levels from
-3
(red towards blue rotation) to
+3
(blue towards red rotation).
I’m going to come back to these individual items in detail
with separate sub-sections in a bit, but first we need to deal
with Picture Controls in a more general sense.