Histogram

[hjoseph7]

Everybody knows if the values on the histogram are bunched up to the left it means an under exposed or low-key

image. When they are bunched to the right, that means an over exposed or high-key image. However what does it

mean when the histogram values are bunched at the bottom of the histogram ? Sometimes I get histograms that are

so thin they look like the letter 'U" . There is a thin line at the right of the histogram, maybe a thin line to the right

and another thin line at the bottom. What exactly does this mean, or how do I interpret this information ?

[syed]

<p>Apart from the over and under exposure, no single tone dominates the picture. Imagine photographing a sliding gray scale from light to dark where each brightness level is equally probable.</p>

[jeffrey_synn]

<p>If your "U" has the peaks at the extreme left and right of the histogram (both black and white), it means the scene has more dynamic range than the sensor can handle. You can live with it (allowing one extreme to clip in favor of the other), slap on a grad ND filter, or bracket for HDR processing later.</p>

[randywilson]

<p>A U-shaped histogram represents an image that is maximally contrasty, with much of the image consisting of very dark pixels and much consisting of very bright pixels and not much in between.</p>

<p>The histogram is just a two-axis graph with tonality from dark to bright represented on the horizontal axis and number of pixels represented on the vertical axis.</p>

[scott_ferris]

<p>A chessboard from above filling the frame...........</p>

[allardk]

<p>It means you had a high-contrast scene. A silhouette taken against bright sun or something like that will produce it. In this answer I assume you meant "There is a thin line at the <strong>left</strong> of the histogram, maybe a thin line to the right and another thin line at the bottom.", and not "There is a thin line at the right of the histogram, maybe a thin line to the right and another thin line at the bottom."<br>

The histogram just shows you the relative abundance of different levels of brightness in your image. Histogram bunched up on the right may also mean you photographed white horses in the snow, correctly exposed.</p>

[ben_goren]

<p>Harry,</p>

 

<p>Try an experiment. Next time there’s a sunny day and you’ve got your camera

handy and some spare time, set up a stage outside. You want the sky and the sun in the top half of

the frame; the more the merrier (use a long lens). The bottom half of the frame should be an open

box on its side, lined with black cloth. Make sure the box itself is shaded.</p>

 

<p>The answers to your questions will reveal themselves.</p>

 

<p>Another experiment: fill the viewfinder with a gray card. Manually adjust exposure so the bug is

exactly on one of the stop marks. Examine the resulting histogram. Adjust the exposure to put the

bug on another stop mark, and compare the histogram with the first shot.</p>

 

<p>By now, you can probably visualize the results, but do the experiments anyway. You’ll

learn a lot.</p>

 

<p>Cheers,</p>

 

<p>b&</p>

[hjoseph7]

Ben thanks I'll try your experiment. Like Allard said I panic when I see "There is a thin line at the left of the histogram, maybe a thin line to the right and another thin line at the bottom" of the Histogram.