Nikon Z 7 Reference Manual page 149

D
Playback Zoom
To zoom in on the photograph when the
histogram is displayed, press X. Use the X
and W (Q) buttons to zoom in and out and
scroll the image with the multi selector. The
histogram will be updated to show only the
data for the portion of the image visible in
the display.
D
Histograms
Histograms show tone distribution, with pixel brightness (tone)
plotted on the horizontal axis and the number of pixels on the vertical
axis. Camera histograms are intended as a guide only and may differ
from those displayed in imaging applications. Some sample
histograms are shown below:
If the image contains
objects with a wide range of
brightnesses, the
distribution of tones will be
relatively even.
If the image is dark, tone
distribution will be shifted
to the left.
If the image is bright, tone
distribution will be shifted
to the right.
Increasing exposure compensation shifts the distribution of tones to
the right, while decreasing exposure compensation shifts the
distribution to the left. Histograms can provide a rough idea of overall
exposure when bright ambient lighting makes it difficult to see
pictures in the display.
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