Dynamic range. Part 1

Instead of a beautiful sky, the sunset shot turned a white spot? Or, on the contrary, it was possible to capture the sunset, but below is only a black background? They photographed a man in front of the window, and behind him in the frame a white veil formed? It's time to figure out where such errors come from and how to fix them! Surely you noticed that sometimes it’s very difficult to show both the bright sun and dark details in the frame: either the sky turns out to be overexposed, or the lower part of the frame becomes too dark. Why it happens? The fact is that the camera is able to perceive a limited range of brightness. It is a dynamic range. In the days of film, this concept was called "photographic breadth."

The lack of dynamic range in the frame: the sky is "lost", instead of it - a white spot.
NIKON D810 / 18.0-35.0 mm f / 3.5-4.5 Installations: ISO 100, F14, 25 s, 22.0 mm equiv.
The sky is saved, all details are included in the dynamic range.
NIKON D810 / 18.0-35.0 mm f / 3.5-4.5 Installations: ISO 31, F20, 6 s, 22.0 mm equiv.
When is the lack of dynamic range most often felt? In practice, the photographer is constantly faced with the problem of insufficient dynamic range. First of all, it will be noticeable when shooting contrasting scenes. A classic example is shooting at sunset. It will not be so easy to capture both the bright sun and the shaded areas at the bottom of the frame, the earth. Lack of range is also felt when photographing in backlight (for example, if you shoot in a room opposite the window). All areas that are not included in the dynamic range in the image are either too light or dark, lose all the details. This, of course, leads to a loss in image quality, technical marriage. Some examples of scenes with a wide dynamic range:
Almost any landscape
Some city sketches
Shooting frames with the moon; night shooting in the city
Backlit portraits

What is the dynamic range of the camera? How to measure it?

So, the dynamic range (DD) is a characteristic of the camera, which is responsible for what range of brightness it can show on one frame. Usually manufacturers do not indicate this parameter in the technical specifications of the camera. Nevertheless, it can be measured by looking at how many details in a dark and bright areas of the frame can transmit a particular camera. Compare: the smartphone’s camera has a narrow dynamic range, and the Nikon D810 SLR camera is wide.
A frame made on a smartphone camera. Details are lost both in bright areas (sky) and in dark areas (bushes). Instead, there are white and black spots in the photo. This is an example of a narrow dynamic range.
Frame made on a reflex camera. Details are saved both in bright areas (all shades of the sky are visible), and in dark. This is an example of a fairly wide dynamic range.
In addition, there are special laboratories that measure the characteristics of cameras. For example, DXOmark , in the database of which there are a lot of tested cameras. Note that the specifics of testing this laboratory is such that the dynamic range is measured at minimum ISO values. So, at higher ISO values, the picture may change slightly. Dynamic range is measured in exposure steps (EV). The more exposure levels a camera can display on a photograph, the wider its dynamic range. For example, the Nikon D7200 has a dynamic range of 14.6 EV (according to DXOmark). This is an excellent result, however, it is worth noting that in general, the dynamic range is usually higher for cameras with full-frame sensors, such as Nikon D610, Nikon D750, Nikon D810. But the dynamic range of compact cameras can be only 10 EV, for smartphones - even less. Note that the potential of SLR cameras (including their dynamic range) can be estimated only when working with RAW files . Indeed, many in-camera settings will affect JPEG images. For example, the camera can greatly increase the contrast of images, narrowing the dynamic range. On the other hand, many cameras can artificially expand it when shooting in JPEG, but more on that later. How to ruin the dynamic range in the photo? Common mistakes Even if the camera has a wide dynamic range, this does not guarantee that photographs will display all the details in dark and bright areas. Consider the main mistakes of photographers, leading to a significant decrease in dynamic range and poor study of details.
  • Exposure Errors . Exposure errors are always fraught with the fact that either overexposed or “blackened out” areas appear on the photo. A frame ruined by incorrect exposure will not save even a wide dynamic range.
Consider an example of a overexposed frame: Theoretically, the dynamic range of the camera for this plot should have been enough, but there was a loss of detail in the bright parts of the frame (in the sky) due to incorrect exposure. The frame was too bright. The reverse situation is that the frame is underexposed, dark. This time the details were lost in the dark parts of the frame.
  • Processing errors . Rough processing of photos on a computer or the use of filters for in-camera image processing can greatly narrow the dynamic range on your frames. Therefore, do not abuse the excessive increase in contrast, work with color saturation, exposure correction, etc.
Original frame: all details are preserved thanks to a wide DD and competent exposure of the picture.
The photographer overdid it with the processing - the details in the dark and bright areas were lost.

We keep within the dynamic range

Often, even when shooting complex scenes with a large difference in brightness, you can not resort to any complicated tricks to expand the dynamic range. You just need to correctly use what the camera can give.
  • Choose the right conditions for shooting . To get high-quality shots, you need to choose the appropriate lighting conditions. Often the photographer drives himself into such conditions in which it is practically impossible to make a high-quality picture. Instead of trying to capture a too contrasting plot, you should think: perhaps it is better to choose a different angle, a different time for shooting or lighting. For example, the sunset sky in brightness is balanced with the earth after sunset. By the way, it’s not always worth taking the sun in a frame. Think about whether you can do without it. So you can avoid unnecessary overexposure. This also applies to shooting portraits in front of the window. It is enough to take a couple of steps from the window and take it to the side of it - the bright window will not turn out to be overexposed, and beautiful side lighting will fall on your model.
Taking this picture, I did not include in the composition the rising Sun, located just to the right of the frame borders. So I saved myself from overexposures in the area of ??the solar disk.
When shooting a portrait in nature, you can not include the sun in the frame. The main thing is to get beautiful lighting from him.
  • Watch the exposure . As we have already said, in order to preserve the maximum detail in a photograph, it must be correctly exposed. Pay attention to the exposure settings , use the appropriate metering methods and a histogram. Also always view the captured frames, check their brightness. If necessary, make duplicates lighter or darker, so that later there is plenty to choose from.
  • Take pictures in RAW . If you are shooting a complex scene, it is always better to have a field for maneuver. The RAW format will provide you with an entire airfield, because absolutely all information about the image will be stored on the camera’s matrix. During processing, you can make the dark areas of the picture lighter or even “stretch” the details a bit in the bright parts of the frame. Please note that brightening dark areas of the frame with the RAW format is much better than darkening light ones. Therefore, preserving the light areas of the image, photographers sometimes specially make frames darker than necessary, so that during processing they "pull out" the necessary details from the shadows. Such processing will make it possible to do almost any modern RAW converter. Including Nikon Capture NX-D. On the expansion of the dynamic range with its help we will prepare special material.
Source frame
Shadows are “extended” in the RAW converter
In the next part of the lesson we will talk about the possibilities of expanding the dynamic range. Some of them are hidden in the camera itself and are available to any photographer. Stay with us!

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