Exposure Compensation: How and When to Use the +/- Control

Exposure compensation is the control marked +/- that tells the camera to make its automatic exposure brighter or darker than its light meter suggests. It matters because the meter is built to make every scene come out a medium tone, so snow turns gray, night turns murky and backlit faces go dark until you correct it.

The control is measured in stops, usually in one-third steps across a range of three to five stops either way. Below: why the meter makes the mistakes it does, how to work out the right value for any scene by counting stops instead of memorizing a list, what the control changes in each shooting mode, and how to check the result.

What the +/- control does

In any automatic exposure mode, the camera meters the scene and picks settings to hit a target brightness. Exposure compensation moves that target. At +1 the camera aims one stop brighter than its own reading, which means twice as much light reaching the sensor. At -1 it aims one stop darker, or half as much. At +2 it is four times as much, at -2 a quarter. The meter keeps working and keeps following the light; every reading is simply shifted by the amount you set.

This is not a brightness slider applied to the finished picture. To make a picture brighter the camera has to leave the shutter open longer, open the aperture wider or raise the ISO, and each of those has a side effect: motion blur, less depth of field or more noise. Which one moves depends on the shooting mode, covered further down.

The control takes one of three forms:

• A dedicated dial on the top plate, marked from -3 to +3. You can see the setting at a glance, even with the camera off.
• A +/- button that you hold while turning a command dial. The value shows on a scale in the viewfinder and on the screen.
• A command dial that acts directly in the automatic modes, with no button needed. This is fast, and easy to knock by accident.

The scale in the viewfinder reads like a ruler with zero in the middle. Each large mark is one stop and the small marks between are thirds. A pointer at the second small mark to the right of zero means +2/3. Cameras that move in half stops show one small mark between the large ones instead.

With an electronic viewfinder or the rear screen, the preview usually brightens and darkens as you turn the dial, as long as the camera’s exposure preview (sometimes called exposure simulation) is switched on. Some cameras turn that preview off with flash attached or in manual mode, and through an optical viewfinder nothing visibly changes at all. In those cases you judge the result by reviewing the picture.

Not sure why one stop means double the light, or how a stop relates to the EV numbers in your manual? Exposure value explains the scale, and the exposure triangle shows how shutter speed, aperture and ISO trade stops with each other.

Why the meter gets fooled

The camera measures light reflected from the scene. It cannot know whether it is looking at a white wall in dim light or a gray wall in bright light, because both can send the same amount of light to the sensor. So it makes an assumption: that the scene, averaged out, should be recorded as a medium tone, known as middle gray. For a typical view with some sky, some shadow and a mix of colors, that assumption is close enough. The meter is not broken when it gets a snow scene wrong; it is doing exactly what it was designed to do.

It fails when the scene is not average:

• Mostly bright scenes. Snow, pale sand, fog, a white wall, a page of text. The meter reduces exposure to pull all that brightness down to a medium tone, and white turns gray.
• Mostly dark scenes. A night street, a black dog on dark ground, a performer on an unlit stage. The meter increases exposure to lift the darkness to a medium tone. Blacks turn to murky gray, lights burn out, and the shutter speed becomes needlessly long.
• A small subject against a very different background. A person in front of a bright window, or a bird against the sky. The background fills most of the frame and sets the exposure, leaving the subject too dark. A bright subject on a dark background has the opposite problem: the background pushes exposure up and the subject burns out.

Multi-segment metering (called matrix, evaluative or multi, depending on the maker) compares the scene with patterns the maker has built in, and it already corrects some of these cases in part. It may brighten a snow scene somewhat without being asked. That is why every value on this page is a starting point: a camera using center-weighted or spot metering does no such guessing and usually needs the larger figure, while multi-segment metering often needs the smaller one.

Want to see a meter fooled, and fix it? The camera simulator has a Snow scene that comes out too dark and a Live music scene that comes out too bright until you dial in compensation.

Count the stops: working out the value for any scene

The usual rule of thumb is “bright scene, add exposure; dark scene, subtract.” It works for snow and night streets, and then fails for sunsets, silhouettes and a white swan on dark water, all of which are bright subjects that need minus. A better method gives the right direction every time, and a number to start from.

1. Find what is setting the reading. With multi-segment or center-weighted metering, that is whatever fills most of the frame. With spot metering, it is whatever sits under the spot.
2. Decide what tone you want that area to be in the finished picture.
3. Count the stops between that tone and middle gray on the ladder below. That count, with its sign, is your compensation.

Tones in a photograph sit on a ladder with rungs roughly one stop apart. The meter puts whatever it reads on the middle rung. You tell it which rung the area really belongs on.

• Pure white, no detail: Typical surfaces: The sun, a bare bulb, specular glints on water. Compensation if this area sets the reading: Nothing to aim for: these clip, and that is acceptable.
• White with texture: Typical surfaces: Snow in sun, white paper, white feathers, a white shirt. Compensation if this area sets the reading: About +2.
• Light: Typical surfaces: Pale sand, light concrete, fog, pale skin in sun. Compensation if this area sets the reading: About +1.
• Middle: Typical surfaces: Green grass in sun, clear blue sky away from the sun, weathered wood, a gray card. Compensation if this area sets the reading: 0.
• Dark: Typical surfaces: Dark foliage, tree bark, dark blue denim. Compensation if this area sets the reading: About -1.
• Black with texture: Typical surfaces: Black cloth, black fur, dark wet rock. Compensation if this area sets the reading: About -2.
• Pure black, no detail: Typical surfaces: Deep shadow, a silhouette. Compensation if this area sets the reading: -3 and below, usually reached by exposing for something else.

The figures are approximate. Real surfaces vary, meters from different makers are calibrated slightly differently, and multi-segment metering will already have nudged the exposure part of the way. Treat the ladder as a way to predict the direction and the size of the correction, then check the result.

Run the method on the hard cases and the contradictions disappear:

• Snow filling the frame: the snow sets the reading and you want it white with texture, so about +2, or +1 1/3 to +1 2/3 with multi-segment metering.
• A white swan on dark water: the water sets the reading. The subject is the brightest thing in the frame but it is small, and water a little darker than middle wants a little minus, around -2/3. At zero the meter would lift the water and push the feathers to pure white.
• A sunset with a dark foreground: the black land pulls the average down, so the meter adds exposure and the sky washes out to pale orange. You want the land black and the sky rich, so take some of that back: -1/3 to -1.

Nearly everything in the sunset is bright, yet it works because the sky is held to a saturated red and the trees go solid black; brightening it would turn the red pale and the trees gray. Sunset photography and silhouettes go further into both.

Try the snow case in the simulator below: with Evaluative metering in an automatic mode, use exposure compensation so the snow comes out white instead of gray, and see which rung of the ladder gets you there.

Want the full system this ladder comes from? The zone system divides the same range into eleven named zones and uses them to plan exposure and development together.

What it changes in each shooting mode

A picture can only get brighter if the shutter stays open longer, the aperture opens wider or the ISO rises. Exposure compensation uses whichever of those the camera is controlling in the current mode. Knowing which one moves tells you what the adjustment will cost.

• Aperture priority, fixed ISO: What compensation changes: Shutter speed. What to watch: +2 turns 1/60 into 1/15, slow enough to blur a handheld shot.
• Aperture priority, Auto ISO: What compensation changes: Shutter speed until it reaches the minimum you allowed, then ISO. What to watch: Plus compensation in dim light raises noise.
• Shutter priority, fixed ISO: What compensation changes: Aperture. What to watch: No further effect in that direction once the lens reaches its widest or smallest aperture.
• Shutter priority, Auto ISO: What compensation changes: Aperture, ISO or both. What to watch: Depth of field may change with each adjustment.
• Program: What compensation changes: Shutter speed, aperture or both. What to watch: Check both numbers after adjusting.
• Manual with Auto ISO: What compensation changes: ISO. What to watch: Minus compensation cannot go below base ISO; plus stops at your ISO ceiling.
• Manual, fixed ISO: What compensation changes: Nothing in the picture. What to watch: You have set all three values, so there is nothing left for the camera to move. On some cameras the dial only shifts where the meter scale shows zero.
• Full auto and scene modes: What compensation changes: Often unavailable. What to watch: Switch to program mode to get the control back.

Two consequences follow. First, compensation has limits. If aperture priority is already at the longest shutter time the camera allows, or Auto ISO is already at its ceiling, more plus compensation does nothing. Second, manual mode with Auto ISO is still an automatic exposure mode, and exposure compensation is the only way to make its pictures brighter or darker without giving up the shutter speed or aperture you chose. Camera modes explained covers what each mode leaves to the camera.

Starting values by scene

These are the ladder worked out in advance. Set the value, take one frame, check it, and adjust by a third or two thirds of a stop. After a few outings they become habits.

• Evenly lit scene with mixed tones: Start at: 0. Why: The meter’s assumption holds.
• Snow filling the frame, sunny: Start at: +1 1/3 to +2. Why: Keeps snow white with texture.
• Pale sand, bright beach: Start at: +2/3 to +1 1/3. Why: Sand is lighter than a medium tone but darker than snow.
• Fog and mist: Start at: +1 to +2. Why: Fog should look luminous, not like dirty gray.
• Person against a window or bright sky: Start at: +1 to +2. Why: Exposes for the face and lets the background go bright.
• Bird or aircraft against overcast sky: Start at: +1 to +2. Why: A white sky is several stops brighter than the subject’s underside.
• Bird or aircraft against clear blue sky: Start at: +1/3 to +1. Why: Blue sky away from the sun is close to a medium tone.
• White subject on a dark background (swan on dark water, white flower in shade): Start at: -2/3 to -1 1/3. Why: The dark surroundings push the meter up and the whites clip.
• Dark subject filling the frame (black dog, dark fur, dark machinery): Start at: -1 to -1 2/3. Why: Keeps black looking black.
• Sunset or sunrise sky as the subject: Start at: -1/3 to -1. Why: Deepens color and protects the brightest cloud.
• Deliberate silhouette: Start at: -1 to -2. Why: Pushes the subject to solid black.
• City street at night: Start at: -2/3 to -1 1/3. Why: Night should look like night; protects lit signs and windows.
• Spotlit performer on a dark stage: Start at: -1 to -2. Why: The dark stage fools the meter into burning out the performer.

Topic guides give more detail on the hardest of these: winter photography for snow, fog and mist for scenes with no dark tones at all, and backlighting for subjects with the light behind them.

The eagle shows the trade you accept with plus compensation. The sky has gone almost to plain white, and that is the price of seeing brown feathers and the pale tail instead of a black cutout. When the background matters as much as the subject, compensation alone cannot hold both, because the scene has more range than one exposure can record.

Night works the other way. Left at zero, an automatic mode would try to lift this pavement and sky toward a medium tone, which stretches the exposure, turns each lamp into a larger burned-out blob and removes the feeling of darkness. Minus compensation keeps the mood and shortens the shutter time as a bonus. Night photography covers the rest of the settings.

Try the dark case in the simulator below: a lit band in a dark arena, where the meter lifts the darkness and washes out the performers until you dial in minus compensation.

“Correct” is a choice you make

There is no single right exposure for a scene. The meter’s answer is one opinion, and the ladder only gets you to the result you decide on. A foggy morning can be a moody gray or a bright, airy white. Pictures made mostly of light tones are called high key, mostly dark tones low key, and compensation is the quickest way to either in an automatic mode.

A meter left alone would pull this fog down toward middle gray and the morning would look dull. High key and low key photography explores both styles.

Checking the result: histogram and highlight warnings

The picture on the rear screen is a poor guide to exposure, because screen brightness and the light you are standing in both change how it looks. Two tools are more reliable.

The histogram is a graph of the tones in the picture, from black at the left edge to white at the right. Use it to check compensation like this:

• Snow, fog, sand: the main hump should sit in the right third, close to the right edge without piling up against it. A hump in the middle means the white has come out gray: add more.
• Night and low-key scenes: the main hump belongs on the left. A hump in the middle means the scene has been lifted too far: subtract.
• A spike jammed against the right edge: highlights are clipped to pure white. Subtract until it pulls away, unless the clipped area is something that should be featureless, such as the sun or a bare lamp.

A useful check: each stop of compensation slides the hump a clear step along the graph. If you add a whole stop and the hump barely moves, the camera has probably run out of range, and the mode table above tells you where.

The highlight warning makes clipped areas flash in playback. It answers the question the histogram cannot: where in the picture the clipping is. A flashing sky behind a correctly exposed face may be acceptable. A flashing forehead or wedding dress is not. Mirrorless cameras can show a live histogram, and many offer zebra stripes that mark near-clipped areas before you shoot, so you can set compensation with no test frame at all.

If you shoot raw, the file usually holds a little more highlight detail than the histogram suggests, because the graph is drawn from a processed preview. Treat that as a safety margin, not as license to ignore the warning. Deliberately pushing exposure toward the right edge for cleaner shadows is covered under expose to the right.

Want practice before you are in front of a snowfield? The histogram guide has a tool built from real photos shifted from two stops under to two stops over, so you can watch the graph move and judge which version is right.

Metering a middle tone instead of guessing

Compensation corrects the meter after it has been fooled. The other approach is to give the meter something it cannot be fooled by: a surface that really is a middle tone.

• A middle tone in the scene. Green grass in sun, clear blue sky away from the sun, weathered wood or a mid-gray rock. Spot meter it, or fill the frame with it, then hold that reading with AE lock while you recompose, or copy the settings into manual mode.
• A gray card held in the same light as the subject. It is a middle tone by design, so a reading from it needs no correction at all.
• An incident light meter, which measures the light falling on the subject rather than the light bouncing off it. Because it never sees the subject, a black dog and a white swan in the same light get the same reading, and both come out right.

Each tool has its place. Compensation is ideal when the meter is wrong in the same direction for many frames in a row, such as a morning on a snowfield. When only one composition is the problem, locking a reading from a middle tone is quicker. When the light is steady and the subject keeps moving between light and dark backgrounds, such as a bird crossing from sky to trees, no single compensation value is right for both, and manual exposure set once for the subject is the stable choice.

Want to see how each metering pattern reads the same backlit scene? Camera metering modes has a tool that shows what matrix, center-weighted and spot metering measure and the exposure each would pick.

Flash compensation, bracketing and phones

Exposure compensation vs flash exposure compensation

A flash picture contains two exposures at once: the ambient light already in the scene and the burst from the flash. They have separate controls.

• Exposure compensation adjusts the ambient part: how bright the room, sky or background is.
• Flash exposure compensation, marked with a lightning bolt beside the +/- symbol, adjusts only the power of an automatic (TTL) flash: how bright the flash-lit subject is.

For outdoor fill flash, a typical combination is exposure compensation at 0 or -1/3 to keep the sky, and flash compensation at -1 to -1 2/3 so the flash lifts shadows without looking like flash. One caution: on some cameras the main compensation dial changes ambient and flash together by default, and a menu option restricts it to ambient only. Check which yours does by shooting a flash frame at +1 and seeing whether the subject, the background or both get brighter. Balancing flash and ambient light explains the two-exposure idea in depth.

Bracketing builds on your compensation value

Auto exposure bracketing takes a set of frames at different exposures, for example at -1, 0 and +1. On most cameras the set is centered on the current compensation value, not on zero. With +1 dialed in for a snow scene, a one-stop bracket of three frames gives 0, +1 and +2. Compensation puts the middle frame where you think the right exposure is, and the bracket covers you either side.

Exposure compensation on a phone

Tap the screen to set the point the phone focuses and meters on, then drag the small sun icon or brightness slider that appears: up for plus, down for minus. Pressing and holding usually locks focus and exposure so the setting stays put while you recompose. Most phones have a fixed aperture, so the phone changes shutter time and ISO instead, and its processing may lift shadows on its own, so check the result the same way. Phone camera settings covers the rest of the controls.

Common mistakes with exposure compensation

Turning the wrong way. Darkening a snow scene because it “looks bright” gives gray snow, and brightening a sunset because it is bright washes it out. Fix: you are correcting the meter, not the scene. Ask what is setting the reading and where on the ladder it belongs.

Forgetting to set it back to zero. The value stays put between shots and, on most cameras, after the power is switched off. The +1 2/3 you set for snow will overexpose everything you shoot indoors that evening. Fix: make zeroing the dial part of putting the camera away, and glance at the scale whenever you pick it up. Some cameras offer a menu option that resets the value at power-off.

Ignoring what the adjustment did to the shutter speed. In aperture priority, +2 in dim light quadruples the exposure time and can blur the picture. Fix: read the shutter speed after adjusting, and raise the ISO or use Auto ISO with a minimum speed.

Expecting it to work in full manual. With shutter speed, aperture and ISO all fixed, the dial changes nothing in the picture. Fix: change one of the three settings yourself, or turn on Auto ISO.

Trying to rescue a subject by clipping everything else. Plus three on a backlit face in front of a sunlit street gives a pale face in a white void. Fix: move the subject, turn them toward the light, or add fill flash. Dynamic range explained shows why some scenes cannot be held at any single exposure.

Relying on raw to fix it later. Blown highlights contain no detail to recover, and lifting a badly underexposed file brings up noise. Fix: get within about a stop in camera, erring toward protecting highlights.

Try this: white paper, black cloth, ten minutes

You need a sheet of white paper, something black with a bit of texture (a jacket or a camera bag) and even light, such as open shade or a room lit by a window. Set aperture priority, a fixed ISO and multi-segment metering.

1. Fill the frame with the white paper and shoot at 0, +1 and +2. Note the shutter speed for each: it should double from one frame to the next.
2. Fill the frame with the black object and shoot at 0, -1 and -2.
3. Compare the two frames shot at 0. They will look much closer to each other than paper and cloth do in real life, both pulled toward gray.
4. Look at the histogram for each frame and watch the hump move one step at a time.
5. Pick the frame where the paper looks white with visible texture, and the frame where the black looks black with visible weave. Those values are your camera’s corrections for a white-filled and a black-filled frame with this metering pattern.
6. Set the dial back to zero.

Judge it this way: the right white frame has its hump close to the right edge without a spike touching it, and the right black frame has its hump on the left with the texture still visible when you zoom in. If your chosen values are close to +2 and -2, your meter behaves much like the ladder; if they are smaller, your multi-segment metering is already correcting part of the way, and you now know by how much.

Want to check you can predict which way the meter will go wrong, and by how much? Try the camera metering quiz, which covers metering modes, exposure compensation and histograms.

Frequently asked questions

Does exposure compensation work in manual mode?

Only if Auto ISO is on, in which case it changes the ISO the camera chooses. With a fixed ISO in manual mode, you control every setting, so the dial has no effect on the picture. On some cameras it shifts the zero point of the meter scale instead.

Is it the same as brightening the photo afterwards?

No. Exposure compensation changes the real exposure, by moving the shutter speed, aperture or ISO, so it changes how much light the sensor records. Brightening in editing stretches the tones already captured, which cannot bring back clipped highlights and lifts noise in the shadows.

Why are my snow photos gray?

The meter assumes the scene should average out to a medium tone, so it darkens a frame full of white. Add +1 to +2 stops of exposure compensation and check that the histogram sits near the right edge without touching it.

What does +1 EV mean?

One EV is one stop, so +1 EV of compensation means twice the exposure the meter suggested and -1 EV means half. Most cameras move in steps of one third of an EV. Confusingly, on the EV scale used for settings a higher number means less light, so +1 EV of compensation gives a combination one EV number lower.

Why did my exposure compensation stop having any effect?

The camera has run out of adjustment. In shutter priority the lens may already be wide open, in aperture priority the shutter may be at its longest time, or Auto ISO may be at its ceiling. Change the setting you control, or raise the limit.