bar chart

bar chart - This is a diagram of the tone distribution of pixels in the image.

Bar graph. Article from Radozhiva

Bar graph. Article from Radozhiva

From left to right (horizontal) the brightness is indicated, and from bottom to top (vertical) the amount of area of ​​the photograph of a particular tonality. It is often said that vertical columns simply show the ratio of the number of pixels of a particular tonality. That is, the chart shows how much light or dark shades prevail in the picture, how many green or red or other shades of colors in the picture are more. Histograms are different. In photography, mainly use three types:

  1. Total bar graph exposure (which is in the figure below).
  2. A histogram for each of the three primary colors, such a histogram is often called RGB - red, green, blue - red, green, blue (as in other examples)
  3. Hybrid Bar Chart for General exposure and for primary colors (often, just a histogram across exposure overlay the RGB histogram).

How to use a histogram

bar chart

bar chart

The histogram shows how many dark or bright areas in the image, what is the overall balance exposure snapshot.

A photograph with a huge dark area. The histogram is "shifted" to the left.

A photograph with a huge dark area. The histogram is “shifted” to the left.

The histogram is often divided into 3-4 parts. The part of the histogram from the very left edge is called “shadows” or dark tones, since this area shows how strong the dark areas of the image are. The far right part is “lights” or light tones, so this part shows how many light sections are on the histogram. The middle is “partial shade” or midtones. The far right part is sometimes called the area of ​​illumination, if there is a splash in the histogram in the very right corner, then most likely the photo is overexposed.

There are more light areas in the photo than dark ones. Histogram peak shifted to the right

There are more light areas in the photo than dark ones. Histogram peak shifted to the right

Why is a histogram useful?

  1. It makes it easy to control under-exposure (underexposed image) and overexposure (overexposed). When overexposed, the peak (vertex in the diagram) will be visible on the right side of the histogram, and if underexposed, the peak will be observed on the left side of the histogram.
  2. Fine tune exposure
  3. Control the color channels in the photo. Using the histogram, you can determine the color saturation of the image.
  4. Contrast control. According to the histogram, you can easily guess how much the picture is contrasted.
There are more dark areas in the photo than light ones. Histogram peak shifted to the left

There are more dark areas in the photo than light ones. Histogram peak shifted to the left

What should be the histogram?

There is no single answer to this question. Ideally, the histogram view should resemble bell shape (when I was studying at the institute, this form was called a Gaussian). In theory, this shape is the most correct - after all, the image will have few very bright and very dark objects, and the middle tones in the photo will prevail. But as practice shows, everything very much depends on the type and idea of ​​the photo itself. A histogram is a purely mathematical description of photography (art), and as you know, it is very difficult to describe beautiful things mathematically, especially with the help of such a simple method as a histogram. Therefore, there is no need to bring the image to a template form using the histogram. The histogram should be used simply as an additional tool when creating a photo.

Histogram pictures

Bar graph photos. The tone is shifted to the area of ​​light tones. The contrast is not high.

When do I use a histogram?

Personally, I use the histogram in only two cases - when you need to check the exposure of the image in bright light, when the image itself is practically not visible on the camera display. It can be the conditions of a summer beach or the bright sun in the mountains. Under such conditions, it is simply not visible what is in the picture, therefore, I look at the histogram to approximately estimate the deviations exposure. And secondly, I use the histogram when editing photos, it is very convenient to determine the key in which the photograph was taken by the histogram, and sometimes adjust the photo by adjusting part of the histogram curve. For example, sometimes I just take the “light” in the histogram and use the slider to move them to the left - I move them in the shadow, the photo is obtained without overexposure. Such a histogram, as in the examples in this article, gives ViewNX 2.

Classic Histogram Photo

Classic Histogram Photo

conclusions

Histogram - a useful tool for the photographer. Whether or not to use the histogram is up to you, you can do fine without it, or still figure out its properties and use it when processing photos or adjusting them accurately exposure.

Thank you for attention. Arkady Shapoval.

Add a comment: Mitya

 

 

Comments: 54, on the topic: Histogram

  • Svirida Sergiy

    Crazy for a story

    • Yosef

      Enlgehtining the world, one helpful article at a time.

  • Alex

    The lens is enviable. With this you can shoot down police helicopters.

  • Dimanych

    The first photo haunts you ... Was the cabin of the attraction ripped off by chtol?

    • Arkady Shapoval

      Yes, torn off.

      • Dimanych

        Horror. I somehow didn’t carefully read the article, and I began to google the disaster pictures of the rides

        • Arkady Shapoval

          Relax. This is photoshop, "ala" joke.

  • Ivan

    You can also remember that the BB and the intra-chamber processing affect the intracameral display of the histogram. Therefore, it is not always possible to determine, for example, an overexposed image from the histogram on the camera, just as not every overexposed image can actually be such (only for RAW, of course). For a more accurate assessment, it is better to use a computer, in particular, a good Rawnalyze program.
    A very interesting article about histograms here: http://www.libraw.su/articles/digicam-white-balance-problems.html

  • Vladimir

    if I'm not mistaken, you have a small mistake: ”The part of the histogram from the leftmost edge is called“ shadows ”or dark tones, since this area shows how strong the dark areas of the image are. The extreme LEFT part with “highlights” or light tones, so this part shows how many light areas are on the histogram. ” Correct “left side” to “right side”

  • Vladimir

    no, not mistaken ... I am inattentive :)

    • Arkady Shapoval

      The examples show that the more “dark areas”, the larger the peak to the left in the histogram rectangle.

    • Siberian

      He “broke” his head. Why are there both "dark tones" and "light tones" on the far left? Can still fix that "light tones" in the extreme right side, as by the way, and signed in the picture.

      • Arkady Shapoval

        I apologize, this is what the eyeglasses are doing. Everything is fixed.

  • Maksim

    Thank you!

  • Yuliya

    Thank you for the article! Very informative for me. I’m just now getting a training at a photo school, and I need material for self-study. Thanks.

  • Alexander

    Hello. In the example, I also have four histograms on my Nikon, these are red, white, blue and green. As they say on Google, but I did not find anything. Why exactly four, and not one. For what it was done.

    • Arkady Shapoval

      This is in my article.
      The camera shows:
      General exposure histogram (white)
      A histogram for each of the three primary colors, this histogram is often called RGB - red, green, blue - red, green, blue (as in other examples), to understand the level of power of certain colors.

      • Andrey Kuznetsov

        In addition to the basic RGB histograms that show brightness, many cameras now have separate color histograms for the red, green, and blue channels. The RGB histogram displays a combination of all three channels, but in a separate color channel you can check which colors form the peaks in the image. Using the histograms of individual channels, you can also check the correctness of the white balance setting by photographing a card painted in 18% gray. If on the histogram all three channels (red, green and blue) display graphs of individual color channels with a peak at the same point, this indicates the correct color balance setting. If there are differences between the channels, an additional adjustment will be required to achieve the correct white balance.

        • Kirill

          I apologize for the amateurish question, but why exactly 18% and what does it mean in general - 18% gray?

          • KalekseyG

            18% of the light absorbs, and 82 returns

            • Kirill

              And why exactly 18 to use?

  • Alexander

    Thanks, figured it out.

  • Dilara

    Arkady, your site is the BEST, I read, I study, I teach !! And the selection of lenses and a description of them is generally invaluable! Thank you!

    • Arkady Shapoval

      Thank you.

  • MELHAUZ

    I’ve been waiting for this article, since the purchase of the photo I wanted to know what a histogram is and what it is eaten with !? Now even more or less I can navigate the histogram. Thanks Arkady, what would I do without you :)

  • Alexander

    On the camera and on the computer monitor, different photos in terms of brightness, that is, on the computer they are much darker. The monitor is calibrated, so you need to calibrate the monitor on the camera, how to do it right? And are there any other reasons?

    • Arkady Shapoval

      Different devices have different parameters, it is logical that the display will be different. On cameras, only brightness adjustment is usually available.

      • Alexander

        So how to achieve the same result?

        • Arkady Shapoval

          Adjust the settings of the computer display to the settings of the camera. This is not a correct solution, but solves the problem.

          • Alexander

            Thanks! But I think the problem will not be solved, since other users of the same Internet have different monitor settings. I think it's better to set up the camera then, but in general it's strange, the same shouldn't be ...

          • F Cyril

            What would be the right decision?

  • Vadim

    Thank you very much, Arkady! I enjoyed reading a clever and comprehensive article.
    Best wishes to you!

  • Vyacheslav

    And how to see the histogram on the camera screen? I have a Nikon D3100. And one more question can be seen only at the photo already taken, or can it be taken when photographing?

    • Arkady Shapoval

      You must properly set the display mode when viewing. On some cameras, you can watch a histogram on Live View.

      • Alexey

        Good day! Arkady!

        First time on your site. I read the article on the histogram. Very interesting and useful information. Thank you!

  • Vladimir

    I always read you with pleasure, thank you very much. Here's what I noticed here: "splash" on the histogram, then, most likely, the photo is overexposed "... probably a mistake

  • Sasha

    Arkady tell me on the main photo cradle with ice came off what le?

    • Artyom

      So it is written that this is a photo montage.

  • Alexander

    Faced this when shooting at dusk. I’m shooting it manually, I don’t look at the exposure meter, because in the absence of daylight it lies, and if you set the exposure on it, the frame is overexposed. I try it manually, the frame is normal. But the histogram shows that the frame is underexposed! It turns out the histogram is not always correct? Does it correspond to a light meter? who knows?

  • Eugene

    The site is very useful, written in a clear language, I learned a lot, by the way I also have a photo from the roller coaster.

  • Sergey V.

    Indeed, the histogram is convenient to use, especially for me as a beginner. Example: shooting on a winter street in the beginning of twilight. The histogram is displayed. It clearly shows under- and overexposure of the picture. This is followed by an exposure compensation of + or -. Works - as it should.

  • Sergei

    Something seems to me that the article is still damp. Everyone praises the author, but personally I (as a complete noob, but wanting to learn) in the process of reading it, there were questions to which there are essentially no answers.
    For example:

    “Why is a histogram useful?
    1. With its help it is easy to control underexposure (underexposed image) and overexposures (overexposed). When overexposed, the peak (vertex in the graph) will be visible on the right side of the histogram, and if underexposed, the peak will be seen on the left side of the histogram. ”
    In the photo above this paragraph, a model lies in the snow, the histogram is shifted to the right. Pop to it “There are more light areas in the photo than dark ones. The peak of the histogram is shifted to the right ”So what does this example show? Did you get an overexposed or normal shot? It looks like a normal picture, because it is winter, snow ...
    The picture below shows a night street view. Caption “There are more dark areas in the photo than light ones. Histogram peak is shifted to the left ”It is also logical that the histogram is shifted to the left. Isn't that how it should be? Where is this border between under- and over-? When should you adjust exposure and when not? It would be nice to highlight this point.

    "2. Fine-tune the exposure"
    The question correlates with the question to item 1. When and how to adjust this exposure looking only at the histogram?

    “3.Control color channels in the photo. The histogram can be used to determine the color saturation of the picture. ”
    Good, determined. And what is the use of this? What does it give to get a good shot?

    “4. Control the contrast. By the histogram, you can easily guess how contrasting the picture is. "
    The same thing - how to control and guess?

    In the last paragraph, again in passing: "Under such conditions, you simply cannot see what is in the picture, therefore, I look at the histogram to roughly estimate the exposure deviation." How would you know by what algorithm the author is working in the process of your “prediction”?

    In general, if the author supplemented the article with at least a couple of paragraphs with explanations and examples, then its usefulness would increase significantly. This also applies to other articles on this resource. Simply, this is the most unexplained of all that I have read so far :)
    In any case, thanks to the author for his work.

    • Arkady Shapoval

      In photography, as in any other business, you need a little imagination and impromptu :) The rest will take note and refinement.

  • LisNick

    Thanks! I am glad that the chic, comprehensive articles! As soon as you remember all this ((at least write

  • anonym

    thank you

  • Lion0608

    Do you know what a comfortable installation is? Damn, I'll probably get everyone with my research, but in visual art there should definitely be a concept of a comfortable visual, I just don't know because of my lack of education. I might be wrong. But a Gaussian bell is just an option when the photo corresponds to a picture that is harmonious for the eye (I do not take into account DOF, in relation to it it is also correct, but in a different plane). Those. there is no “skew” to dark or light, when the eye needs to “adjust” and nothing “clings” too much (too sharp blackouts, when psychologically the vision tries to “peep” what's there, too blind spots, under which, psychologically, a person is also drawn to unravel, what lit up there). Accordingly, a photographer who is trying to sharpen the viewer's attention can deliberately leave blackouts or, on the contrary, brighten the picture. But it’s good when it’s understanding and conscious. In principle, the same problem with DOF. Now it has become very fashionable to blur the background with and without reason. But it will always be harmonious only in facial portraits, in photo details. This kind of simulates the situation when a person concentrates and mentally makes a ZOOM, and all other objects “defocus”, when DOF is artificially achieved at medium size, on general shots, it freezes a little. Although there is an addictive effect. Well, people over 20 years old are accustomed to fast clip editing, modern children have a completely different reaction and perception of the world. But this is so, thinking aloud.
    A histogram, as it turned out to be good to use in test mode. In the video where there are large sections to edit, so far I initially tried, for a separate scene, to make general delimiters on the sides so that there are no strong crashes across the entire assembly piece, and then fine-tune it already inside according to circumstances.

    • Alexander

      The author just emphasized that the Histogram is just a kind of mathematical representation of the relationship between brightness and contrast in a particular picture (photo frame). And of course, you can't talk about the artistic value of a photo based only on the Histogram readings ..

  • Kirill

    And you can clarify -
    “From left to right (horizontally) the brightness is indicated, and from bottom to top (vertically) the amount of area of ​​the photo of a particular tonality. It is often said that vertical bars simply show the pixel ratios of a given tonality. " - since we are talking about mathematics - how is the amount of area measured? Not in square millimeters?

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