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Old 10-05-2011, 02:09 PM   #14
Geo31
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Join Date: Mar 2003
Location: Houston, TX, USA
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Quote:
Originally Posted by RonnieRenaldi View Post
The histogram graph consists of all the pixels in your picture, from the darkest to the brightest. The left side of the histogram depicts how many "dark" pixels you have captured; the right side, how many "bright" pixels you have captured.

Picture is too dark (underexposed):


Picture is not too dark and not too bright (correctly exposed) - "good" histogram:


Picture is too bright (overexposed):
I've been meaning to correct this for some time. I don't know if it's been addressed somewhere else in this thread, so forgive me if it has.

The above is partially correct and partially Internet/DSLR myth.

The histogram indeed tells you the distribution of "light and dark pixels." It does NOT tell you anything what so ever whether the photo is properly exposed or not.

This is very much an Internet myth. Some subjects are predominately dark and some are predominately light. As such, a properly exposed image of the subject will have the distribution of "light and dark pixels" skewed to one side or the other.

In brief, you have to consider the subject and distribution of light and dark areas inherent to the subject. What you want to do is to have as much detail in the light and dark areas without blowing out the light areas or muddying the dark areas.

For more in-depth understanding of this, I'd recommend studying the Zone System, where tones are numbered 0-10 generally. Here is a link to the Wiki article on the Zone System:

http://en.wikipedia.org/wiki/Zone_System

Lots of people know the name Ansel Adams and are familiar with his work. He was one of the creators of this concept and his photos are stunning because of how he manipulated not only the printing of his images, but the exposure as well to produce the highest dynamic range possible in a single exposure.

Again, you don't have to have an even distribution of the tones in an image (as suggested above). You want to faithfully reproduce the range of tones in the subject (or even intentionally manipulate them, but that is more advanced than this discussion is intended to be).
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