What is exposure value?

February 11

16 min. to read

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Is the picture so dark that you can't see the model? Or is the whole shot so over-exposed that it looks like you're taking a picture of a white sheet of paper? All this means you have the wrong exposure. So, what does EV stand for in photography? Read what the exposure value is to take well-balanced HDR photographs.

Few photographers know what exposure value is. However, every photographer faces it constantly dealing with exposure compensation and post-processing of RAW-files on a computer. You can often hear the phrase “take bracketed shots at -2/0/+2EV” in conversations about HDR. But what is EV? How to calculate it and why do we really need it? If you don't know what is EV on a camera, this article is for you.

Exposure in photography is the result of how much amount of light reaches the sensor or camera film in a given amount of time. If there is not enough or less light, the picture will be too dark - underexposed, and if there is too much light, the scene will be overexposed. Let's find out what exposure is and how to set and measure it, as well as what camera settings affect it.

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What is Exposure Value?

If you are a newcomer, then of course you have a question about what is EV in photography. As we said before, exposure is the amount of light that reaches the camera sensor when shooting a single photograph. Factors that affect non-flash exposure are:

  • Aperture: how large the opening into the camera is
  • Shutter speed: how much time the light is allowed to enter
  • ISO: the sensor sensitivity of the camera

Exposure value is the combination of these three issues. Note, that light meter EV. Different figures of aperture, shutter speed, and ISO can give one and the same EV value, but the images you take will differ. Your camera measures the scene in EV, than it adjusts the three above factors to make a perfect shot depending on the kind of scene.

Why do You need to Change Exposure Value Settings?

The correct shooting settings affect the clarity and brightness of the subjects in the photo.

If not enough light reaches the sensor, the picture will be darkened. In this case, it is said that the exposure was low. If there is a large amount of light, on the contrary, the image is very bright. Then we say that an unjustifiably high value was chosen. In both cases, there are no halftones in the images, and the quality of such photos suffers.

Modern digital photographic techniques are equipped with a number of automatic modes which the camera will adjust and manual exposure adjustment. For beginners, it is important to understand the principles of manual adjustment and equivalent settings, to learn how to use the histogram, which gives an indication of how evenly the light is distributed over the frame.

Digital cameras make mistakes with EV light despite their cost or how many different features they have. Complicated scenes can make your camera sensor perceive the light in improper ways. So, EV camera settings are very important.

If you quickly take shots without checking and adjusting EV, you will probably have many underexposed or overexposed shots. Photo processing software such as Aurora HDR will help you to set EV in photography, but it is sometimes impossible to regain details in light and dark parts of the picture.

You have to follow certain rules and camera EV settings when shooting high-contrast scenes, especially when you do not have a tripod. Adjusting the EV setting on the camera will give you the ability to shoot a white cat on a white background without making it go gray or invisible.

The exposure value determines the brightness at which the exposure time is set. A different EV value is recommended for each value of sensor sensitivity, depending on the shooting conditions. You can find tables of recommended EV values in instruction manuals and literature. By understanding the relationship between exposure and aperture settings, the owner of a digital camera will be able to be creative in the process of taking pictures.

You will also need to set EV camera exposure to control the depth sharpness depending on what effect you want to reach. What is the scale for EV and how can you calculate this value? EV chart will help you find the answers below.

How to Calculate Exposure Value?

What is the exposure value formula? Explore the relation between Exposure Values, f-stops and shutter speed. Have a look at the table and EV charts for choosing the right value for you. The adjustments of EV photography you commonly pick up are limited by your digital camera's dynamic range and the case at hand.

What are examples of adjusting different exposure values? Here is the exposure settings chart. You can freely use all of the following EV camera settings.

Outdoor photography:

  • Artificial light from ads at night 9 to 10 EV
  • Artificial light from fountains or buildings at night 2 to 5 EV
  • Natural light at golden hours 12 EV
  • Natural light at night -2 to -11 EV
  • Snowy or sandy scenes 16 EV
  • Clear sunlight scenes 12 EV

Indoor Photography:

  • Artificial light in offices, galleries and gyms 8 to 10 EV
  • Interior at home or Christmas tree lights 5 EV

Let's also talk a little about manual mode. In this mode (M from Manual), the photographer adjusts the basic digital camera settings himself. The exposure value chart is affected by three main parameters: aperture, shutter speed, and ISO.

In the era of film photography, exposure was adjusted with correct exposure and light meter - a combination of aperture and shutter speed settings. You can't change the ISO there - it's a constant value that depends on the parameters of the film.

Aperture is a parameter that determines how much light dials the sensor. The amount of light is regulated by the degree of opening of the so-called aperture diaphragm blades. It is denoted by the letter f and a number. For instance, f/1.8, f/5.6. The smaller this number is, the wider the aperture is open and the brighter the picture will be. 

The aperture also affects sharpness and depth of field (DoF) - the area in which objects are depicted clearly without blurring. The bigger the aperture number, the more areas of the picture will be in sharpness. That's why the aperture is raised for group portraits. You can also simply use aperture priority mode.

A small aperture value increases the chance that the focus will miss, but it creates a beautiful blur in the background. The shape of the bokeh depends on the design of the lens - the more aperture blades, the more rounded the bokeh pattern. You can give it any shape you want on your own and use a different combination of apertures.

Shutter speed controls how long light enters the camera. It does this by keeping the camera shutter open, allowing the photosensitive element (sensor, film) to collect light. The shutter speed is displayed using a fractional number (e.g. 1/125, 1/1000). The smaller the number, the darker the picture will be. The higher the number, the brighter the picture. 

If the shutter speed is slow and you have the camera shutter open for a long time, any motions of your hands will blur the picture. You can easily fix it by holding the camera still with a tripod and not moving it until the shutter closes.

ISO indicates the sensitivity of the sensor to light. In digital cameras, this function can be influenced, but in the pre-digital era, ISO remained unchanged and depended on the light sensitivity of the film. It is displayed as a whole number - 100, 640, 800, etc. The higher the number, the brighter the picture. 

Setting the ISO sensitivity too high may decrease the quality of the picture by introducing noise. At too high an ISO value, there is so much noise that the picture gets scattered. That is why there is a working ISO, which is the maximum sensitivity where noise does not get in the way. It depends on the camera's capabilities (and, generally speaking, its price) and can be either 800 or 6400.

By combining all three parameters, you can also correctly set a proper exposure, while maintaining the maximum quality.

How to adjust your camera settings for HDR shots?

The high dynamic range of a photograph indicates the difference between the lightest and the darkest parts of the scene. A single-exposure shot on current camera sensors cannot capture both bright and dark details.

Bracketing is the method we use to capture maximum details. It means taking a series of shots at 1 or 2 photo exposure value stops. If your camera supports auto-bracketing mode, you will have to push the shutter once. For everyone who starts to learn what HDR photography is, it's critical to master the process of bracketing. 

You can adjust your camera manually to -2/0/+2EV stops for taking one underexposed, one overexposed and one normal set of shots. If you shoot complicated scenes at night or on a bright sunny day, you can take up to ten shots at 1EV stop per each of them. A tripod is a valuable tool to ensure your shots remain level and motion free between each EV exposure. 

HDR greatly exceeds the EV you can shoot letting you expand the dynamic range of your digital camera and precisely expose various elements of a photo without having to sacrifice details or artistic quality. So, now you will no longer have the question of what is exposure value.

How to merge bracketed shots into a beautiful HDR photo?

Bracketing allows you to take several identical frames with different exposure value settings. For example, three frames: medium brightness, darker and lighter. You can do the same with white balance to get a medium shot, a cooler shot, and a warmer shot. Why do I need Exposure Bracketing?

To get three shots with different brightness when you are unsure of your exposure value settings. You'll end up with several shots to choose from, from which you can select a good one.

Get several frames so you can combine them later in a graphical editor. This is useful if the scene contains areas with strong brightness variations. For example, when shooting landscapes. 

One picture will have beautiful clouds in the sky, but the lower part of the frame will be in deep shade, while the other will have a completely white and textureless sky and rich, detailed grass. By combining these two shots, you get a perfectly exposed photo. This widens the dynamic range of the image. This effect is called HDR.

Import photos from your camera onto your Mac or PC as you usually do. You will need a specific software for merging bracketed exposures into an HDR image. Aurora HDR is one of the most popular apps, which is also available as a free demo version.

Take few steps and get the job done:

  • Launch Aurora HDR and load the brackets;
  • Click Create HDR.

The proprietary tone mapping algorithm makes HDR images look natural with different exposure values. You can find available controls for extra editing in the right sidebar. One-click presets change the effect from natural to extreme. Color, tone and contrast controls are available for selective and global editing. Get rid of noise and half-visible objects with corresponding controls.

Save, export or share your results after you finish. Keep in mind that Aurora HDR was made for both Mac and Windows users. One click and the job is done.

Use Aurora HDR for free for 14 days.

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