histograms (Page 3): My exposure technique pretty much renders the histogram rather useless. I occasionally look at it during PP. However, this will give you a pretty good idea.

rmalarz Loc: Tempe, Arizona

My exposure technique pretty much renders the histogram rather useless. I occasionally look at it during PP.

However, this will give you a pretty good idea. http://en.wikipedia.org/wiki/Image_histogram

You can also do a google search on digital photography histogram
--Bob

steve49 wrote:

what can be done w a histogram?
what value does it have?

I see it for each pic but have no idea what it is used for or how it can be useful.

pecohen Loc: Central Maine

On a related, but somewhat different topic, while I think I understand histograms generally, I sometimes am not sure how the horizontal axis is established. Does it represent the range of eight-bit values (I once saw this stated) or is it the 12-bit values or the 16-bit values or is it something else altogether? I don't see much documentation on this but I do notice that histograms for the same image look quite different - sometimes, even different histograms shown for the same image by the same software can look different.

Does it seem to anyone else that we need to have some standardization regarding this - or at least some good documentation.

rmalarz Loc: Tempe, Arizona

The horizontal axis is simply the number of values available, As it pertains to digital images it is 256, 0 through 255.

As for documentation, simply google

digital image histograms

--Bob

pecohen wrote:

On a related, but somewhat different topic, while ... (show quote)

pecohen Loc: Central Maine

rmalarz wrote:

The horizontal axis is simply the number of values available, As it pertains to digital images it is 256, 0 through 255.

As for documentation, simply google

digital image histograms

--Bob

Yes, I've seen this much documentation before. Unfortunately the documentation seems not to apply to all histograms I've seen - or perhaps there is some other reason that different histograms for the same image do not always look the same.

Apaflo Loc: Anchorage, Alaska

pecohen wrote:

Yes, I've seen this much documentation before. Unfortunately the documentation seems not to apply to all histograms I've seen - or perhaps there is some other reason that different histograms for the same image do not always look the same.

There can be differences if the graph is for composite or luminance values as opposed to R, G, and B channels. The horizontal scale might be linear instead of logarithmic, and the vertical scale may or may not be normalized to have at least one full scale value.

Otherwise, if all these kinds of things are the same... the same image will have exactly the same histogram. Of course the "same image" does not mean just that it originated with the same snap of the shutter, it means literally it is the same at every pixel. Edits change the histogram!

camerapapi Loc: Miami, Fl.

It is time to do some reading. A histogram, especially the color one, is an invaluable aid to exposure. I cannot go over all the details but you have to know that at each edge clipping occurs.
The most important thing here is to make sure that the histogram should be extended to the right without clipping (reaching the extreme right) because that simply means that your bright areas are markedly overexposed.
Do your homework because histograms and basic exposure are most important to good photography.

rmalarz Loc: Tempe, Arizona

I'm not too quite sure what you mean by the different histograms for the same image. Are you referring to the colour channel histograms, and also the "brightness" histogram?
--Bob

pecohen wrote:

Yes, I've seen this much documentation before. Unfortunately the documentation seems not to apply to all histograms I've seen - or perhaps there is some other reason that different histograms for the same image do not always look the same.

RWCRNC Loc: Pennsylvania

You Tube has many videos

OnDSnap Loc: NE New Jersey

camerapapi wrote:

It is time to do some reading. A histogram, especi... (show quote)

pecohen Loc: Central Maine

camerapapi wrote:

It is time to do some reading. A histogram, especi... (show quote)

This was actually the problem that has troubled me. On numerous occasions, I've adjusted exposure so that there is no clipping on the right and then, without making any other changes, in another histogram, I find that the image is indeed clipped on the right - and I'm not sure why.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

rmalarz wrote:

My exposure technique pretty much renders the histogram rather useless. I occasionally look at it during PP.

However, this will give you a pretty good idea. http://en.wikipedia.org/wiki/Image_histogram

You can also do a google search on digital photography histogram
--Bob

So what is your exposure technique?

agillot

it is the basic tool to check your pictures exposure .if you take pictures in bright sunlight , it become almost impossible to evaluate your pictures on the camera screen due to sunlight , the histogram is perfectly visible , it is not fool proof , it takes some time to get used to it , but when you do , you will use it all time .

gsmith051 Loc: Fairfield Glade, TN

To me a histogram is just another function to get the photo to look like the real view. I never use it on the camera while shooting, only in LR to adjust the greys. Keeping the bell shape curve in the center provides a better visual appeal in most cases.

DWU2 Loc: Phoenix Arizona area

steve49 wrote:

what can be done w a histogram?
what value does it have?

I see it for each pic but have no idea what it is used for or how it can be useful.

Try Googling the term Exposing to the Right.

rpavich Loc: West Virginia

PixelStan77 wrote:

Histogram shows the tonal range you have captured from white to black and if you are over or under exposed.
Read this article and you will then understand the histogram.
http://digital-photography-school.com/how-to-read-and-use-histograms/

actually...only partially true. It DOES show the range of tones either in the field of view or captured in the image (before or after hitting the shutter) but it cannot tell you if your shot is over or underexposed. The distribution of tones doesn't tell you that.