Zebra - Canon Camera Hackers Manual

Ignore Boundary Peaks allows clipping a specified number of pixels (0–
f
32) at the left and right side of the histogram. Typically, this situation
arises when the subject matter is small and placed on a monotonous
background, as in night shots. A large black area would result in a high
peak at the left side of the histogram, and the remaining information
would vanish because of scaling. Removing these peaks makes the his-
togram readable again.
Another way to deal with peaks is provided by Auto Magnify. If enabled
f
and the histogram is filled to less than 20 percent, the Y-axis is enlarged
and peaks are clipped. The clipped peaks are marked with a red dot, and
the amount of magnification is displayed above the histogram.
Show Histo Ev Grid adds four or five vertical grid lines to the histogram
f
that indicate Ev values. The lines have a distance of one Ev (one f-stop).

4.3.4 Zebra

Another convenient way to control exposure is the Zebra feature. While the
histogram informs you about the tonal range of the complete image, the
Zebra feature identifies image areas that are under- or overexposed. These
areas are displayed with a pattern overlaid on the image to make them
stand out visually.
When enabled in the CHDK menu, Zebra areas are displayed by half-
pressing the shutter. The feature also works in Replay Mode when half-
pressing the shutter, allowing you to assess the image quality after the
shot has been taken.
Again, there are various options to configure:
Draw Zebra enables or disables the feature.
f
Zebra Mode determines how the overexposed or underexposed areas
f
are overlaid:
Blink 1 Solid overlay, blinks twice every second.
Blink 2 Solid overlay, blinks every second. This is my favorite. When there is
something blinking on the screen, I take a closer look to see what's
wrong, but the blinking is not so fast as to make me nervous.
Blink 3 Solid overlay, blinks every two seconds.
Solid Solid overlay, no blinking.
Zebra 1 Striped overlay, thin diagonal lines.
Zebra 2 Striped overlay, fat diagonal lines.
4.3 Exposure
Figure 4-22
The Zebra submenu configures the
Zebra mode.
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