How do u use a histogram?

[The Ever Optimist]

Hello to all
My camera, Olympus 750 UZ has a histogram feature - i know thats a good thing but dont know why
All advice on this will be highly appreciated!
Kunal

[mtbbrian]

You will probably get a better answer regarding your issue on the Digital Camera Forum.
There are several different forums here that are all specialezed in one of the many aspects of photography.
If you have any questions, regarding anything on PR.com, feel free to email me.
Good Luck!
Brian

[Asylum Steve]

Like Brian said, this isn't the right forum for this question, but I'm here, so I'll try to give you an answer.

A histogram shows the dispersion of pixels across a tonal range with black on the left side, midde gray in the, uh middle, and white on the right side. The peaks of the histogram correspond to the amount of pixels with that particular tonality.

Once you have this understanding, you can clearly see how a histogram can be useful in adjusting the exposure of your shot.

Keep in mind there is NOT one single correct histogram that you should be striving for. Like an exposure meter, it is something that often has to be interpreted.

An evenly lit scene with a large amount of middle tones when properly exposed should show a histogram that peaks in the middle with very low black and white amounts.

However, take a high key shot that is almost all white with a small amount of gray or black detail. When properly exposed it would show a histogram weighed heavily to the right, the main peak being white or close to white pixels.

Ok, without getting too technical, a good working habit is to, just as a lot of folks reflective meter read off a gray card, take a shot with a neutral gray card filling most of the frame and getting the same amount of light as the basic scene. The histgram for this shot, as I mention before, should have its peak falling roughly in the middle. If it does, your exposure is good.

Now, with digital, you also need to be more aware of the highlights. Like slide film, you don't want to blow those out if you can help it. So, using your gray reading as a ballpark figure, shoot the scene (without the card) and see if the histogram shifts a lot to the right.

If it does, and you do not want a blown out effect, you're going to have to adjust the exposure to bring the highlights down a bit. If it shift to the left a lot, you may need to open up the exposure to get more shadiow detail.

Basically, the histogram gives you a quantitative measurement of something the human eye has a great deal of difficulty perceiving...

Hello to all
My camera, Olympus 750 UZ has a histogram feature - i know thats a good thing but dont know why
All advice on this will be highly appreciated!
Kunal

[another view]

What Steve and Brian said.

I'll add that it's very difficult to judge exposure by looking at the LCD monitor. When you check the histogram, look at the left and right sides. If the "graph" that you see is sharply cut off right at either end, then you've lost something. If it's on the left, then you have no detail in the darkest areas of the shot. If it's on the right, then the highlights are blown.

As Steve said, there isn't necessarily a right and wrong here, only if you don't get the exposure that you intended to get. On a high key shot, you would blow the highlights to keep the background white.

[The Ever Optimist]

Like Brian said, this isn't the right forum for this question, but I'm here, so I'll try to give you an answer.

A histogram shows the dispersion of pixels across a tonal range with black on the left side, midde gray in the, uh middle, and white on the right side. The peaks of the histogram correspond to the amount of pixels with that particular tonality.

Once you have this understanding, you can clearly see how a histogram can be useful in adjusting the exposure of your shot.

Keep in mind there is NOT one single correct histogram that you should be striving for. Like an exposure meter, it is something that often has to be interpreted.

An evenly lit scene with a large amount of middle tones when properly exposed should show a histogram that peaks in the middle with very low black and white amounts.

However, take a high key shot that is almost all white with a small amount of gray or black detail. When properly exposed it would show a histogram weighed heavily to the right, the main peak being white or close to white pixels.

Ok, without getting too technical, a good working habit is to, just as a lot of folks reflective meter read off a gray card, take a shot with a neutral gray card filling most of the frame and getting the same amount of light as the basic scene. The histgram for this shot, as I mention before, should have its peak falling roughly in the middle. If it does, your exposure is good.

Now, with digital, you also need to be more aware of the highlights. Like slide film, you don't want to blow those out if you can help it. So, using your gray reading as a ballpark figure, shoot the scene (without the card) and see if the histogram shifts a lot to the right.

If it does, and you do not want a blown out effect, you're going to have to adjust the exposure to bring the highlights down a bit. If it shift to the left a lot, you may need to open up the exposure to get more shadiow detail.

Basically, the histogram gives you a quantitative measurement of something the human eye has a great deal of difficulty perceiving...

Thanks - will try my luck at using it effectively!