How to view a histogram on a computer. What is a histogram? Histogram in photography: how to use? Do we need to use a histogram?

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In this lesson you will learn: What is a proper histogram and what is it for? Shooting complex exposure scenes: how to avoid “overexposure” and “black holes” in the picture. Exposure compensation and exposure bracketing.

Almost all modern digital cameras, even simple point-and-shoot cameras, have a so-called histogram. Unfortunately, not all amateur photographers know how to use such a useful function, most often simply ignoring it, or even deliberately turning off its display.

The histogram is displayed either when viewing an already captured image, or, in some cameras, a “live” histogram (real-time histogram) is displayed on the screen. In both cases, the histogram can help the photographer quickly intervene in the shooting process and get a normally exposed photo. But the “live” histogram allows you to draw conclusions before pressing the shutter button or, in other words, before taking a picture, which increases the efficiency of shooting and the number of high-quality photographs.

Histogram of a photographic image called a graph of the distribution of pixels with a certain brightness (lightness), where the horizontal axis shows brightness (from 0 to 255), and the vertical axis shows the number of pixels of a given brightness. For example, in the following brightness histogram, a level of 80 corresponds to 1106 pixels out of 120000.

You should know that the histogram is usually mentally divided into three parts - the shadow area, the midtone area and the light area:

Depending on which part of the histogram contains the most pixels, the photo will be dark:

medium light:

or bright:

Of course, the above tone regions can simultaneously be present in the histogram:

It is impossible to say which histogram shape is correct for a good photo. It may look like a hill:

like a bath:

or as something large and shapeless:

The tonal range of the scene being filmed can be very narrow (for example, clouds or mountains in fog):

and very wide, which does not fit into the dynamic range of the photosensitive matrix (shooting in a bright day or night, sunrises or sunsets):

For practical purposes, we only need to know for now about histogram boundaries - they should not clearly rest on the left or right side, as in the picture above. So, for example, if the left border of the histogram is a pronounced peak, then, most likely, the photo is underexposed, or, as photographers say, there are “lost shadows” in it.

Conversely, if the right edge of the histogram represents a peak, then the photo is overexposed, or, as photographers say, there are “highlights knocked out” in it:

Both cases can arise due to an error in determining the exposure by the camera’s automatic system, as well as the photographer’s choice of an inappropriate method for determining exposure - using a central point, center-weighted or average. In any of these options, the histogram will show the problem area, and on this basis the necessary correction can be made. The instructions tell you whether your camera supports exposure compensation and how to do it.

We can express our condolences to the owners of simple compacts, but apart from contemplating the camera’s metering errors in the histogram, they have no correction tool (unless they try to choose a different one) automatic mode). All prosumer cameras and cameras with interchangeable lenses have a “+/-” button (or this function in the camera menu), while holding it you must simultaneously turn the control wheel for exposure compensation.

In order to shift the entire histogram to the right, you need to perform positive exposure compensation. It is necessary to remember that with positive exposure compensation, the exposure increases (depending on the set digital focus mode, either the shutter speed increases or the aperture opens). In the vast majority of cases, exposure compensation in the range from 1/3 to 1 EV is sufficient, while shadows begin to appear and highlights intensify, thus increasing the tonal range of our photograph. If you apply +1/3 EV exposure compensation to the underexposed photo above, you will get the following result.

That's better, isn't it? The left border of the “failed” shadows ceased to be peak-shaped, at the same time, the right side of the histogram shifted to the area of ​​highlights, which made the clouds and sky lighter. But they still remain insufficiently light (we believe a priori that the lightest part of the clouds should be bright white). To do this, you need to make additional exposure compensation, which became +1 EV, so that now the right side of the histogram is very close to the right border.

Thus, the image began to occupy the full tonal range, and began to look quite acceptable.

For overexposed photographs, use negative exposure compensation. In this case, the entire histogram shifts to the left, so details begin to appear in the highlights and shadows appear. If we apply exposure compensation of -1/3 EV to the overexposed image above, we get the following result:

Already better than it was, but still not good enough, since the shadows turned out to be too light and low-contrast. By changing the exposure compensation to -1 EV, we get a completely acceptable picture:

Clouds appeared in the sky, and the shadows became contrasting, so the photo can be used for printing or publishing on the Internet.

It should be remembered that exposure compensation is possible in all camera modes, with the exception of automatic (AUTO) and manual (M). In the latter case, the histogram can be shifted by manually setting the shutter speed, aperture or ISO. It is also very important to know that the appearance of the histogram may change before or after half-pressing the shutter button, since this may open or close the aperture. The “live” histogram will have the same appearance as in the photograph, only when you press the shutter button halfway - this is the histogram you should use to navigate.

So we learned how to use exposure compensation to increase the tonal range or shift it to a darker or lighter area. Now we'll talk about the "exposure bracket".

Exposure bracketing (exposure bracketing)- a shooting technique used to ensure that a photograph is correctly exposed, especially in changing or unusual lighting.

Technically, exposure bracketing (bracketing) involves shooting the same frame with different exposure parameters. If you take a photo, but are not sure that the automatically set exposure will give a guaranteed correct result, you take two more frames: one frame with underexposure from the automatically set exposure (-1/3) and another frame with overexposure from the automatically set exposure (+ 1/3).

The fact is that your camera's light meter may determine that there is too much light (or too little light) on your subject, so the finished photo may be underexposed or overexposed. Having three identical photos with different exposures, if something happens, you will always have a photo with a normal exposure.

For example, on a sunny day, you shoot a scene where there are more illuminated objects around the main subject, such as a sandy beach or snowdrifts. In this case, your camera's average-weighted exposure metering may be fooled large area bright background, and the automation will consider that for normal exposure of the frame it is necessary to close the aperture or shorten the shutter speed (if the settings ISO sensitivity installed manually). As a result, your main subject will be underexposed. By taking another, slightly overexposed frame, you will get a picture with an overexposed background, but a perfectly captured main subject.

Another example is when the background is too dark and the camera will automatically open the aperture or increase the shutter speed more than necessary for the main subject - it may be overexposed. And again, if you used exposure bracketing, you have a frame with a normally exposed main subject and an underexposed background.

Many modern digital cameras have an automatic exposure bracketing function (AEB - Automatic Exposure Bracketing). This means that if you set this mode before shooting, your camera will automatically take three shots: one with an average exposure metering, a second with a slight underexposure, and a third with a slight overexposure. Usually, the default amount of change in underexposure of a frame is -1/3 and +1/3 for an overexposed photo, but in the settings of your digital camera you can change the amount of exposure bracketing to -1 and +1, respectively.

When should you use an exposure bracket? Always when the lighting is different from normal or when there are a lot of shadows or lights in the frame. Use exposure bracketing also when you know you won't be able to return to the location where you want to shoot a rare photo. beautiful frame. For example, the sunset will be more expressive when the photo is slightly overexposed - use exposure bracketing and select the most successful photo at home.

Don't be discouraged if your camera doesn't have AEB - when shooting landscapes you can get great shots using manual installations exposure or applying exposure compensation. Without moving the camera, which is stable on a hard surface (preferably on a tripod), take as many pictures as you need, each time, changing the exposure slightly for all the details in the frame. Then, using your computer, you can combine all the correctly exposed areas into one photo. Of course, you can just slightly change the brightness and contrast of the photo, but believe me, using layer-by-layer overlay of images with different exposures will give the desired result, because Every detail of the photograph will be shot with the required exposure.

So, let's summarize.

1. To obtain a correctly exposed photograph, you can and should be able to use a histogram.
2. The histogram is shifted to the highlight area using positive exposure compensation, and the histogram is shifted to the shadow area using negative exposure compensation. In this case, the shutter speed or aperture may change, depending on the selected shooting mode.

3. If your camera has AEB functions, it is recommended to use this function in difficult scene lighting conditions, when the photographer cannot determine which area should be metered.

Practical task:

1. Set your camera through the menu to always display a histogram on the screen. Please refer to your camera's manual.

2. Set the shooting mode to aperture priority or shutter priority. Take a photo, evaluate the histogram and enter exposure compensation. Take a corrected photo and evaluate the histogram again. If necessary, repeat exposure compensation. Return exposure compensation to zero.

It is advisable to repeat this procedure many times, bringing the actions to automaticity, so that when shooting you don’t have to think about what and where to press, and the plot will be missed.

If you have a tripod, use it.

3. Turn on AEB mode, having previously configured it according to the instructions. Take a series of exposure bracketed photos and evaluate them using the histogram. If you have a graphic editor, do 1) overlay images; 2) correction of the exposure of one of the images obtained when shooting with exposure bracketing. Evaluate the result.

And don’t forget, after exposure compensation or using bracketing, to return these settings to zero at the end of shooting!

In the next lesson #6: Basics of composition. Semantic and decorative layout of the frame. Compositional techniques: perspective, rule of thirds, golden ratio, diagonals. Main and secondary objects of the composition. The main mistakes of beginning photographers.

photo by Mardy Suong Photography

Real-time histograms are one of the most useful functions digital cameras, and most have it modern models. The tools are also available in almost any image processing software. However, the histogram is one of the settings that is most often left to the discretion of auto mode, as many (even experienced) photographers simply do not know how to use it. By learning new skills and ever-evolving technologies, we increase our skill and, ultimately, our self-worth. Therefore, it is worth covering the issues of using a histogram. First, let's review what a histogram is.

The on-screen graphic, expressed as peaks and valleys, shows the degree of brightness and its variations that exist in your photo - ranging from black (0%) to white (100%). The histogram is an accurate and clear “guide” to exposure. It reflects the F-band parameters and brightness levels present in the image. You should get into the habit of looking at the histogram every time you take a photo, and it will be much easier to adjust the exposure. Here, for example, is a typical histogram - with pronounced differences in parts.

The picture shows that in the photo information display window there is a part with histogram data. It can be enabled or disabled in most cameras on the market.

A histogram is a two-dimensional display of the tonal range of a photo, it is indicated on the X-axis. The Y-axis informs about the number of pixels. On the left side are the darker tones, in the center are the medium tones, and on the right are the lighter tones. In the picture above, most of the pixels are in the middle zone. This means that the photo is uniform, there are practically no overexposures or underexposures (extreme left and right values). These are the optimal settings for most shots, but sometimes you need to work in high or low key.

Using a histogram, you can create any photo, including atypical or perfectly balanced ones. Below you can see several examples in which the difference is clearly visible.

There are three different histograms in the figure. In the first example, none of the details of the image are lost, there are no unnecessary shadows or highlights. The highest values ​​are close to the center of the graph, the curve decreases beautifully towards the edges - like a bell. The graph displays a photo with a large number of bright fragments from the mid-tone range.

The second example is a histogram with a distribution over the entire range. The peak on the right edge shows that there are very bright white details in the image, in which all the details are blurred. The third histogram displays the frame in very dark tones, with virtually no brightest areas. There is very little that is completely black in the image and nothing that is 100% white at all.

Which of the above is correct? This is a trick question. The fact is that the histogram is nothing more than a reflection of the tonal range recorded by the camera sensors. She cannot “tell” whether you took the photo correctly or not. There will be a lot of black parts and bright, white lights in the photo - and there's nothing wrong with that. The same applies to a portrait on a pure white background.

Now let's see how the histogram compares to the real world.

Similarly, histograms can be used to produce high- or low-contrast images (over- and underexposure).

Here are high and low key photos and their histograms

A common technique when photographing objects where details in the background are not needed. This technique is used if it is necessary to emphasize the subject itself. Portraits are often made in a low key, in which you want to highlight the contrast and features of the model. In general, of course, using a histogram will not automatically make you more of a professional than you actually are. However, without any doubt, it will teach you to understand the basics of the image and will become a useful tool with which you can improve your results.

Not all photographers take the time to look at the histogram after every shot, but it's worth doing it at least during post-processing of images. The skill of working with it will expand your capabilities and help you move further on the path of mastery.

Digital technology makes a photographer's work much more efficient and faster. Today digital cameras can not only show the result of shooting immediately on the camera display, but also analyze these photographs - show overexposed areas of the frame and a histogram (general and separate for each of the three RGB channels).

The histogram allows the photographer to analyze the frame and instantly make adjustments to the shooting. And thereby save you from unnecessary processing in the RAW converter and Photoshop.

is a graphical representation of the distribution of halftones in a photograph. Horizontally there is a brightness scale, and vertically there is a relative number of pixels with a given brightness.

The histogram is read from left to right, from black to white.

Look at the following examples and you will understand how to read a histogram.

The histogram shows that there are no absolutely black areas in the photo. On the right you can see that there are small overexposed areas in the photo.

The histogram is generally distributed evenly across the entire brightness range. There are small areas of over- and under-exposure, but they are not critical.

The following example shows how to see under- and overexposures using a histogram.

The display will not show how much white background is white. The histogram shows a complete void on the laptop screen, with light gray tones on the body and a white background around the subject.

Looking at the camera screen, it is difficult to understand whether there are losses on the car body. The histogram clearly shows that there are no absolutely black areas, but overexposure on white objects is clearly visible.

The histogram also helps when processing in Photoshop in the Levels mode. See how the histogram and photo look after increasing the contrast.

On the left is the original photo, on the right is the result after a slight increase in contrast. As you can see, the work of contrast stretches the histogram, adding dark and light areas.

Why do we need a Histogram?

All modern cameras are equipped with fairly large and high-quality displays. Why then do we need a histogram?

Displays have their own brightness level, the perception of which also depends on the ambient light. If you look at the display at night, the picture will seem very bright, but during the day, on the contrary, it will appear very faded. Due to the fact that the histogram shows the image as a graph, it is independent of any viewing conditions.

The quality of the camera displays is really high, but not enough to show the difference between almost white and completely white, or the difference between almost black and completely black.

Look at the following photo:

http://www.flickr.com/photos/bigfrank/368734607/

This is just the perfect photo for our situation. Of course it was processed in Photoshop, but that doesn't matter.

As you can see in the photo there are no overexposures or dark areas. The histogram shows us the same thing. Along the edges there are low columns that indicate overexposure from lighting lamps and dark areas in the display case. Otherwise, as you can see, the histogram shows that most of the information is in midtones.

One look at the histogram is enough to make sure the exposure is correct and move on to shooting.

As you already understood, each image has its own histogram; accordingly, there is no correct or incorrect histogram.

The histogram should be considered as a tool for quickly analyzing a photo while shooting (or during processing).

When to use a histogram

Night photography
In the absence external sources Light makes it especially difficult to determine the brightness and contrast of a photograph.

Studio shooting
If you're shooting in a studio and don't have a light meter to measure the power of the devices, you have to work at random, adjusting the camera according to the result on the display. The histogram will more accurately show the situation in the picture.

Product photography
Objects are usually photographed against a white background. The photo can only show areas of overexposure. And the histogram will help you understand how white really is.

Bottom line

As you can see, the histogram is a very powerful and convenient tool for a photographer. This is an absolutely necessary thing for creating technically high-quality photographs. And in our next articles we will continue to talk about interesting and effective tools for working with photographs.

Many novice photographers encounter difficulties in using a histogram in photography, and some do not consider it necessary to use it at all. What is a histogram, how does it work in professional practice, and what does it do for a photograph? What is the best way to correct it - through the camera itself or later when processing the photo through an editor? What should a photographer know about exposure, contrast, light and shade, and other critical values ​​in photography? More about this in the article.

What is this?

So, histogram - what is it? Many times, when photographing some kind of panorama or portrait, you transferred the pictures to your computer and wondered why, with such a bright full-fledged image, they turned out too dark or, on the contrary, overexposed? It is quite difficult to control the brightness of a photo on a small camera monitor by eye, but you can adjust the optimal level. A photo histogram is a tool that shows the distribution of light and dark tones in a photo and allows you to achieve their even distribution.

There are several types of histograms on cameras - with a smooth gradient, with bars, with color and black and white horizontal lines. The most popular one is in the form of a bell. But its operating principle is the same for everyone - this is a graph displaying the brightness of the image from the darkest tones (on the left) to the lightest (on the right).

Before we figure out how a histogram is read in photography and how to use values ​​from 0 to 255, let's find out the opinion of professional photographers and determine for ourselves whether it is needed for a high-quality photo, or whether you can do without it.

Myths and misconceptions about the histogram

There is a lot of debate about whether this brightness graph should be used or not. To understand this, let's debunk a few myths about how and when a camera histogram is used.

• Professional photographers determine the balance of light and shadow “by eye”, without relying on the camera processor.
• Depending on the camera level, the displayed data may be incorrect.
• A photograph does not have to be perfectly exposed; sometimes overexposure or darkening is part of the creative idea.
• A photo histogram is usually only used when shooting in black and white.
• Professionals often trust the processing of RAW format images in Adobe Photoshop, Adobe Lightroom and some other correctors.

In this regard, opinions on the use of graphs are divided into pros and cons.

Opinion “against”

Professionals with a trained eye rarely use this schedule, since it is time-consuming and does not always lead to the desired result. For a beginner, it is very difficult to read it right away and understand in which direction to change the exposure metering values; moreover, some erroneous values ​​during photography will be quite difficult to correct even with correction in the future.

Not all cameras, only professional ones, can give truly correct light and shade values, but they can also make mistakes. Anyway, in the future the image will have to be corrected in Photoshop and Lightroom, so working with the histogram will only take up precious time.

Opinion “for”

What are the benefits for those who know what a histogram is?

• Even if you professional photographer, a second glance at the graph will tell you how rich the picture is in terms of tonal transitions. Moreover, in many digital cameras You can display it directly on the display and look at it without interrupting the creative process.
• If the shooting takes place not indoors (for example, a well-lit studio), but in sunny weather in a park, it will be quite difficult for the photographer to objectively evaluate the image on the screen, since it may reflect and show colors more faded than they really are . In night weather, on the contrary, the photo can turn out deceptively bright. It is also difficult to perceive the accuracy of black and white on the screen and it is not easy to recognize which areas have been “killed” by contrast. For this, a strict evaluation tool is better suited - a histogram in photography.
• Sometimes you can use a histogram to select a camera; it shows the width of the dynamic range, i.e. how many colors the camera can capture when shooting. After all, when buying a camera, it is not always possible to take a picture that will show all the colors from the generally accepted range of 0-255.

Summarizing all of the above, understand what a histogram is in photography, how to use ( practical application), not always necessary, but not superfluous, since there are cases when this knowledge cannot be done without. Therefore, let's learn to read it and put it into practice.

How to read a histogram

So, what is a histogram in a camera and why it is needed is clear. Visually it looks like a graph. On the horizontal axis, from left to right, there are shades from black (dark) to midtones (medium brightness shades) and white (light). The vertical axis indicates the number of pixels of each hue in the image. As a result, we get several columns of different heights; the higher the column, the more of this or that light. Let's look at it in practice.

Underexposed frame

Underexposing means the photo will be too dark. In the graph, the camera histogram is shifted to the left. What to do in this case? This means that there are a lot of dark tones, dark objects, black spots, and almost no light ones. If this is not the intent of the photo, and you are not just shooting a dark subject, go to the exposure settings and add 1-2 points up (value 1.3; 1.7).

Overexposed frame

Overexposure indicates the opposite, that the frame turned out to be overexposed (a lot of light, glare of water, snow in the frame), or you are photographing a white (light) object. Again, if this is not provided for by the plot, go into the exposure and reduce its value to 0.7.

“Correct” frame

Now, knowing what a histogram is in a camera with incorrect exposure values, let's look at a correctly exposed frame. Visually, he looks like a boa constrictor that ate a hat. This means that shadows and light are present and correctly adjusted, and halftones prevail in the photo. This frame looks expressive, contrasty, clear and bright. Plus it will be easier to process.

Low contrast frame

The absence of dark and light areas, in other words, contrast, looks like this. The graph or bars are in the center and missing at the edges. This does not mean that the frame is exposed incorrectly; perhaps this is the author’s idea and there should not be any contrasting elements in the photo. In any case, this ratio can be easily corrected during subsequent processing.

Peaks on the chart

The histogram has two sharp peaks at the edges. This option is often obtained when shooting contrasting objects - earth with dark grasses and a clear blue sky, for example. There is no need to adjust this exposure, since it will not show other values.

High key shot

This kind of pictures are obtained when shooting in light colors - white sky in sunny weather, clothes in light colors. The histograms in such images creep heavily to the right, but this is not an error. The photograph turns out light, airy and allows you to concentrate completely on the subject of photography - an object or person, without being distracted by unnecessary details.

In this case, it is better to leave the exposure at 1, since higher values ​​will lead to overexposure. The brightness of the image can be increased during processing.

Low key shot

There is also the opposite situation, when the graph goes completely to the left - for example, a still life is photographed against a black background. Here, too, you should not be afraid of this shift, and all details, brightness and contrast should be adjusted during the processing process. By the way, about her.

RAW format editing

Having found out what a histogram is in photography, how to use it when processing photos? Every photographer should know that a photo taken in RAW format retains the settings in which it was taken. Therefore, with the help of Photoshop, the master has the opportunity to correct mistakes.

However, there are certain subtleties here too. An underexposed frame is easier to correct with positive exposure, while an overexposed frame is almost impossible to correct. Therefore, it is better to avoid situations with light exposure. To do this, check the frame exposure of each photo after work and use the light indicator in the camera settings.

How to Work with a Histogram in Lightroom

Why use a histogram on the computer if you've already adjusted the shot through the camera while shooting? It's simple, this is necessary in order to evaluate how the photo will look on an average computer. After all, on your Mac-book it may be perfect, but on a friend’s laptop it may be completely dark, and on print it will be completely different, not what you expect.

With Lightroom's histogram, you can get all the complete information about shadows, contrast, brightness, and more.

So, a histogram in photography. How to use it when processing photos? In the program it looks like a rainbow graph. The right side, just like in a camera, is responsible for light, the left for shadows. The density of a particular color is shown in peaks; the lighter the photo, the higher the pixels on the right will be.

The most important thing to pay attention to when processing is loss in light or shadow. If there are no values ​​on the edge of one of the sides, then the photo has lost some detail. For example, dark hair merged into one or the blue sky turned white.

How to fix this? In the diagram you will find two triangles on the right and left. If you click on the left one, shadow losses will be highlighted in blue in the photo. If you click on the right one, the losses will be colored red.

To correct these losses, Lightroom has several tools that are located directly below the diagram, these are:

• fill light;
• exposition;
• contrast;
• shadows;
• sharpness;
• color change and some others.

For example, contrast will help correct a diagram in which all the pixels are pointing high in one direction; such a photo has very low contrast. The hump in the middle speaks about this. But sharp peaks on both sides of the graph indicate, on the contrary, excessive contrast, which would not hurt to reduce.

How to Work with a Histogram in Photoshop

Professional photographers more often use Lightroom to correct exposure and light and shade, since this program has much more complete and convenient tools. But photo adjustments can be done using Photoshop. Here the histogram looks about the same. But using Photoshop, it is convenient to adjust the resolution and format of the image to ensure optimal color rendition when printing images. It is also very convenient to apply filters, correct defects and change photo levels.

If you are adjusting and restoring an old photo, Adobe Photoshop will help you see the correct colors that should be in reality, where highlights or shadows abound.

How to open a histogram in this program? Go to the “Image”, “Correction”, “Levels” tab. You will see a black and white graph in the form of mountains with a range from 0 (absolutely black) to 255. To change the exposure, you need to scroll the gradient bar at the bottom, as well as the markers under the graph itself.

Learning by doing

The main rule that will help you understand what a histogram in a camera means is to practice more, take photographs with different exposure meters, under different lighting, and constantly analyze the resulting images.

Take several identical photographs - one with an exposure of +1, another of +0.3, and a third of -0.7. See how their exhibitions differ. Try switching to a different shooting mode. How has the schedule changed this time?

Check the same pictures using graphic editors, see how they differ from the camera. Only practice can help you better understand the understanding and necessity of using a histogram.

Instead of a conclusion

Of course, not just knowing what a histogram is, but also the ability to use and configure it correctly will help you take truly professional and high-quality photographs. But professionalism consists of a lot of small knowledge about the intricacies of photography.

Naturally, every keen photographer should know the rules for constructing a successful composition, understand why certain manual settings are needed, such as shutter speed, aperture, focus and autofocus, dynamic range, calculation and much more. He must understand what a correct histogram should look like when shooting in normal, low and high key, and when loss of light and shadow is considered normal. Where is it correct to use overexposure to emphasize the composition, and where is it a drawback of the photo? Where does a lot of black in the frame make it difficult to concentrate on the key subject of the photograph?

One thing is for sure, without knowing what a histogram is, it will be quite difficult for you to adjust the settings to get the perfect photo. Whether you use this knowledge constantly or only in some cases is your choice. Good luck with your photo shoots!