How does the histograms in digital cameras work?

Answer 1

Check this article 'Understanding Histograms' at Luminous Landscape...

Answer 2

Histograms give you a graphical representation of the exposure and color balance of your photo. For instance, a photo underexposed skews the histogram to the right. On the other hand, a photo overexposed skews the histogram to the left. But note likewise that a photo that shows a large contrast (like a person in dark clothes lying in the snow) may show an underexposed histogram. SOme cameras also allow you to change the hue and contrast using a histogram.

But the benchmark is always to obtain a bell curve that is skewed towards the middle. Again, this tool does not work all the time especially when subjects are in high contrast, or if the overall tone of the foto is "light" (like a close-up of the face of a caucasian with blonde hair) or "dark" (a close up of the face of an Afican American).

Answer 3

Histograms show whether you have the pic set for a nice, attractive exposure.

The graph is made by measuring the brightness of each pixel, then counting the number of pixels at each level of brightness.

The graph starts with the count of the darkest pixels on the extreme left. Then moves right with the counts of brighter and brighter pixels, until the count of the brightest pixels on the extreme right.

If your camera has a "live" histogram, it will show you how the exposure will come out before the pic is taken. (Some digicams only show a histogram after the pic is taken.)

Do your setup, then check the live histogram. If the curve is mostly to the left, the pic will come out mostly dark. If it is mostly to the right, the pic will come out bright. At the extremes, the pic will be too dark or too bright.

You can change the histogram by changing your setup or camera settings to get more or less light.

In a Program or Manual mode, you can adjust Exposure Value, Aperture, Shutter Speed, or ISO (depending on your camera) to change the exposure result. You can see the change in a live histogram.

In Automatic mode, you usually cannot change the exposure settings, although you may be able to use a Scene mode like Beach (for too bright settings) or Night (for dark settings).

Good Luck

Answer 4

Basically the histograms show you the color balance and light distribution. You can use the histogram to determine if you need to adjust exposure or color balance.