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Old Mar 2, 2003, 8:03 PM   #1
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Default Understanding Histograms....

...I'm still confused in the matter. I mean, websites say that "there is no such thing as a bad Histogram." If so, then why is it so important? I'm still confused as to how looking at the Histogram will help me properly expose photos.

:?:

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Old Mar 2, 2003, 8:10 PM   #2
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Although this page explains it using the Oly E-10, it has the basics for all digital cameras:

http://www.bophoto.com/e-10/histogram.html

BTW I found that page by using Google.com and typing in HISTOGRAM CAMERA.
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Old Mar 2, 2003, 9:57 PM   #3
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Also, it helps to know what the histogram "should" look like based on the scene that you are taking...you can't just look for a mid-range histogram on every shot.

As the article says, you want to keep all or most of the data within the histogram, but at the same time, if you are taking a picture with a lot of highlights, more of the data should be on the right side of the histogram...

For example, if taking a picture out in the snow on a bright day, your camera's light meter will try to make it "average" gray and meter down and underexpose...your histogram will show a beautiful display of peaking at mid range and your picture will be underexposed...you need to give extra exposure compensation and if you want to check your exposure on the histogram you have to know that there should be a bias towards the right hand (bright) side of the graph, though not clipped off with data lost.

The reverse would be true if taking a picture that your camera's meter would normally try to overexpose...a dark scene should have more of the data on the left hand side of the histogram.

Hope that's correct...I'm just trying to figure this stuff out myself and I'm sure some of these nice people will correct me if I'm wrong.
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Old Mar 2, 2003, 10:17 PM   #4
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Quote:
Originally Posted by rych26
Also, it helps to know what the histogram "should" look like based on the scene that you are taking...you can't just look for a mid-range histogram on every shot.

As the article says, you want to keep all or most of the data within the histogram, but at the same time, if you are taking a picture with a lot of highlights, more of the data should be on the right side of the histogram...

For example, if taking a picture out in the snow on a bright day, your camera's light meter will try to make it "average" gray and meter down and underexpose...your histogram will show a beautiful display of peaking at mid range and your picture will be underexposed...you need to give extra exposure compensation and if you want to check your exposure on the histogram you have to know that there should be a bias towards the right hand (bright) side of the graph, though not clipped off with data lost.

The reverse would be true if taking a picture that your camera's meter would normally try to overexpose...a dark scene should have more of the data on the left hand side of the histogram.

Hope that's correct...I'm just trying to figure this stuff out myself and I'm sure some of these nice people will correct me if I'm wrong.
Actually,

This is somewhat along the lines of what I'm looking for, Stu. Thanks-a-bunch for the response. The websites are telling me different things, which is confusing as hell.

:mrgreen:

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Old Mar 3, 2003, 11:39 AM   #5
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The thing to remember about the histogram is it represents real data analysis of pixel brightness. It is the only thing that's not variable, like your lcd display or monitor, which needs calibration of some sort to be meaningful.

The problem is, there is no such thing as the same 'perfect' histogram for each scene if you want what comes out of the cam to look like the original. I've found the most useful part is the white end (smaller number in 255 means less chance of clipping) and at the black end where too big a number here suggests low exposure, unless you're shooting at night.

You can learn a lot by comparing the histograms before and after applying some of the 'auto-correct' tools. They often make consistent sparkly pics, but can take away creativity. Try auto correcting sunset or snow scene shots!
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Old Mar 3, 2003, 9:27 PM   #6
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Here are a couple of good tutorials on histograms:

http://www.shortcourses.com/editing/edit-14.htm

http://www.quiknet.com/~frcn/Histograms.html
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Old Mar 4, 2003, 8:06 AM   #7
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here is another well illustrated one too:

http://www.luminous-landscape.com/tu...stograms.shtml
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