26
Part I
Using the Nikon D90
pattern. (Dr. Bryce Bayer was a scientist at
Kodak who developed this pattern.) The
Bayer pattern lays the fi lters out in an array
that consists of 50% green, 25% blue, and
25% red. The green fi lters are luminance-
sensitive (brightness) elements, and the red
and blue fi lters are chrominance-sensitive
(color) elements. Twice as many green fi lters
are used to simulate human eyesight, given
that our eyes are more sensitive to green
than to red or blue.
The camera determines the colors in the
image by a process called demosaicing. In
demosaicing, the camera interpolates the
red, green, and blue data for each pixel by
using information from adjacent pixels.
Interpolation is a mathematical process in
which sets of known data are used to deter-
mine new data points. (I like to call it an
educated guess.)
When shooting NEF fi les, the RAW
converter handles the demosaicing.
Viewfi nder Display
When looking through the viewfi nder, you
see a lot of useful information about the
photo you're composing. Most of the infor-
mation is also displayed in the LCD screen
on the top of the camera, but it's less handy
on top when you're composing a shot.
Here's a complete list of all the information
you get from the viewfi nder display:
Focus points. The fi rst thing you're
likely to notice when looking
through the viewfi nder is a small
bracket near the center of the frame.
This is your active focus point. Note
that the focus point is only shown
full-time when in the Single or
Dynamic AF setting. When the cam-
era is set to Auto Area AF, the focus
point isn't shown until the Shutter
Release button is half-pressed and
focus is achieved.
Framing grid. When this option is
turned on in the Custom Setting
menu (CSM d2), you see a grid dis-
played in the viewing area. This is
to help with composition. Use the
grid to help line up elements of
your composition to ensure that
things are straight (or not).
8mm [center-weighted] reference
circle. These curves located at the
top and bottom of the AF Area
brackets give you an idea of how
much of an area of the frame is
used for Center-weighted metering.
The curves show you an area of
8mm, which is the default circle
size for Center-weighted metering.
Note that although you can change
the size of the area for Center-
weighted metering (CSM b3), this
display doesn't change.
Black and White indicator. This
icon appears when the Picture
Control is set to monochrome (MC).
For more on Picture Controls, see
Chapter 2.
Battery indicator. This icon
appears when the battery charge is
getting low. When this icon is blink-
ing, the battery has been depleted
and you can't take any more pic-
tures until the battery has been
charged and replaced or a charged
backup battery is installed.
Drukuj stronę