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Make Different Exposures

Of the Same Scene

The light meter in your camera does a good job—most of the time.

However, photographers often need to make more than one exposure of the same scene.

There are six situations where this may be necessary.

Click the situations below for explanations.

If you're not familiar with:

• Using exposure compensation, go to Exposure Compensation.

• Setting your camera light meter to center-weighted and spot metering, go to Light Meter Vision

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #1 - Richer Color

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–0.5

–1.0

Set exposure compensation to -1.0, or thereabouts, to make the colors in a scene richer.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #2 - Eliminate Overexposure

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The brightest areas in the cloud above are overexposed.

The overexposed areas are difficult to edit.

As you can see below, the overexposed areas remain the same even though the photograph was blackened with Photoshop Elements.

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Change Your Exposure If . . .

. . . an important part of a scene is overexposed.

Example

Let's say you're photographing a 1950s convertible in the sun.

A Kim-Novak-look-a-like model is in the driver's seat.

Glints

The glints off of the chrome are overexposed.

Do you need to change the exposure?

No.

The glints are unimportant areas on the photograph.

Dress

However, the white dress that the model is wearing is overexposed.

Do you need to change the exposure?

Yes.

The dress should have some tone.

Check for Overexposure

There are two methods for checking for overexposure.

Check Method #1 - Blinkies

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When online, the overexposed sky above blinks black.

After you press the shutter release, the photograph is displayed on the LCD screen.

On many cameras, overexposed areas will blink between white and black.

Check your camera instruction manual.

This feature is called the blinkies by photographers.

Camera manufacturers use various terms, such as Highlight Overexposure Alert.

If you've downloaded the PDF of your camera instruction manual, search for overexposure until you find the feature.

On many Canon cameras, you have to press DISP to cycle to a screen display that shows the blinkies.

Check Method #2 - Histogram

Your camera can display a histogram.

Check your camera instruction manual.

A histogram is a graph that displays the number of pixels for each tone.

Here's the histogram of the cloud photograph.

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Shadow areas, the trees, are on the left.

Midtones, the snow and the blue sky, are in the middle.

Highlights, the cloud, are on the right end.

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The most important part of the histogram is on the right end.

If there's a spike going up the side of the graph, that means a portion of the photograph is overexposed.

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Solution

Set a minus value using exposure compensation to eliminate the overexposure.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #3 - Subject Not Average Toned

Scenes with Average Tones

Camera light meters work well when the tones in a scene average out to gray.

Since most scenes have a wide range of tones, camera light meters usually produce good exposures.

Scenes with Non-average Tones

When you photograph something that's bright or dark—not average—camera light meters fail.

Below, a white plate and a black bag were photographed.

The camera light meter set wrong exposures.

The white plate isn't white—it's gray.

The black bag isn't black—it's gray.

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No Correction

No Correction

Light Falling on the Scene—Not Measured

The same amount of light was falling on the plate and the bag.

Even though the amount of light was the same—the camera light meter produced two wildly wrong exposures.

That's because camera light meters don't measure the amount of light falling on a scene.

Reflected Light Is Measured

Camera light meters measure the light reflected off of the subject.

They don't measure the light that's being absorbed by the subject.

White Plate

The white plate is reflecting more light than an average scene.

It's absorbing very little light.

So, the light meters thinks it's a bright scene and reduces the exposure.

The white plate becomes a gray plate.

This is what the world looks like to your camera light meter: medium gray.

The camera light meter produces exposures to make photographs look like medium gray.

When you photograph something that's not medium gray—the photograph will be medium gray.

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The camera light meter sees the white plate like this: bright.

It doesn't know that some subjects reflect lots of light.

The camera light meter thinks the subject is bright.

It underexposes the white plate to make it average.

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So, the camera light meter makes the white plate look like this: medium gray.

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Black Bag

The black bag is reflecting less light than an average scene.

It's absorbing lots of light.

So, the light meters thinks it's a dark scene and reduces the exposure.

The black bag becomes a gray bag.

Again, this is what the world looks like to your camera light meter.

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The camera light meter sees the black bag like this: dark.

It doesn't know that some subjects absorb lots of light.

The camera light meter thinks the subject is dark.

It overexposes the black bag to make it average.

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So, the camera light meter makes the black bag look like this.

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Summary

Camera light meters work well when a scene is absorbing 50% of the light—and is reflecting 50% of the light.

The scene has average tones.

Everything in the scene averages out to medium gray.

The white plate is reflecting 90% of the light—and is absorbing 10% of the light.

It's not an average scene.

But—the camera light meter thinks all scenes are 50% reflection and 50% absorption—medium gray.

So—the light meter produces an exposure for a scene with 50% reflection and 50% absorption—medium gray.

You get a gray plate.

(The above percentages are for educational purposes and may not be scientifically precise.)

Solution

Use exposure compensation.

The settings are counterintuitive.

You have to overexpose the white plate.

Try around +1.3 or +1.7.

The sky was overcast, so the plate on the right side isn't blindingly white.

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No Correction

+1.5

You have to underexpose the black bag.

Try around –1.3 or –1.7.

You may want to keep dark scenes a little too gray, so they're more visible.

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No Correction

–1.5

Alternative Solution #1

You can also use autoexposure lock.

All digital SLR camera have this feature.

Point-and-shoot cameras typically don't have the feature.

Do the following.

1) Use center-weighted or spot metering.

2) Point your camera at something that's:

• Average toned.

• In the same light as the subject.

The average-toned area should be in the central area of the frame (center-weighted metering) or in the middle of the frame (spot metering).

3) Press the shutter release slightly to take a light reading.

4) Lock in the exposure:

Nikon

Canon

• Or search your camera instruction manual for autoexposure lock.

5) Point your camera at the subject, and press the shutter release.

Alternative Solution #2

An incident light meter measures the light falling on the subject.

The reflectance and absorption of the subject are ignored.

Therefore, incident light meters don't make mistakes.

The incident light meter is held near the subject, pointing at the camera.

If you're doing lots of still life or portrait photography, consider using an incident light meter.

Note

If you set up a non-average-toned scene to photograph, make sure the light or dark subject fills the frame.

A black Labrador dog surrounded by hay and sky will probably be an average-toned scene.

A headshot of the dog is a non-average-toned scene.

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Limiting what the light meter in your camera can see may be helpful.

Go to Light Meter Vision.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #4 - Merge Exposures (HDR)

If you're photographing a scene with lots of contrast, you can't fit the wide contrast range onto a photograph.

The camera sensor can't handle contrast as well as human vision.

Solution

Photograph the contrasty scene with different exposures.

Use exposure compensation or auto bracketing.

Then, merge the exposures into a single photograph with software.

Example

Below, a covered bridge was photographed.

The first exposure recorded the exterior well.

I used exposure compensation to make two exposures for the interior. 

The three exposures were combined using the PhotoMerge Exposure feature of Photoshop Elements.

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0.0

+1.0

+2.0

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All Three Exposures Merged (0.0, +1.0, +2.0)

Post Merge Editing

After merging, you can tweak the photograph further with the usual editing techniques.

More

Go to:

Combine Two Photographs.

High Dynamic Range (HDR) Photography.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #5 - Backlighting

When a subject is backlighted, the subject is in shadow.

The camera light meter will usually set the exposure for the bright background.

The side of the subject toward the camera will be in deep shadow or may even be silhouetted.

Solution

The best solution is to add light to the shadow area.

Example

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No Change

Exposure Compensation: +1.0

The photograph on the left, above, is what the camera light meter did.

The shadows are too dark.

On the right, the shadows were brightened using exposure compensation.

The value was +1.0.

However, the entire photograph was brightened.

So, while the shadows may be just right now, the tree in the background is a bit too bright.

If the sky had been behind the hydrangea, it would have been more distracting than the too-bright tree.

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Flash

Flash Exposure Compensation: –1.5

Above, fill-in flash was used on the photograph on the left.

The shadows are now too bright.

The use of flash is distractingly obvious.

On the right, flash exposure compensation was set to –1.5.

Both the shadows and the background look good.

Subject Is Close

If the subject is close, like the hydrangea above, add light to the shadow by popping your flash up on your camera.

The flash brightens the subject—and the background doesn't get brighter.

Again, if the flash is too bright, use flash exposure compensation to darken the flash.

Subject Is Far Away

If the subject is a far away, the flash won't illuminate it.

Merge two or more exposures of the scene.

Or, do the following.

1) Use center-weighted or spot metering.

2) Point your camera at the subject.

The subject should be in the central area of the frame (center-weighted metering) or in the middle of the frame (spot metering).

3) Press the shutter release slightly to take a light reading.

4) Lock in the exposure:

Nikon

Canon

• Or search your camera instruction manual for autoexposure lock.

5) Recompose your photograph if necessary, and press the shutter release.

Unfortunately, as the subject becomes brighter, the already bright background will become too bright.

Crop the background as much as possible.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Situation #6 - Expose to the Right (Raw)

If your shooting raw, you may be able to save more information to the raw file by exposing to the right.

The benefit will be seen when editing the shadow areas.

You'll have more information to work with, so noise will be less of a problem.

Do the following.

1) Photograph a scene.

2) Check the histogram for an empty space on the right end of the histogram.

3) If so, use exposure compensation, a plus value, to shift the graph to the right.

Example

A grape vine was photographed.

There's a large empty space on the right end of the histogram.

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No Correction

Empty Space to the Right of the Graph

Below, exposure compensation was used to shift the graph to the right.

The value was +1.3.

The JPEG image on your LCD screen may look overexposed.

But, you're shooting raw.

You're concerned with the quality of the raw file, not the quality of the JPEG thumbnail on the LCD screen.

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Exposure Compensation: +1.3

Graph Shifted to the Right

Caution

The histogram you see when shooting raw is the histogram for the JPEG thumbnail.

So, the histogram is only an approximation of the raw-file histogram.

Therefore, don't try to eek out every drop of dynamic range when shifting to the right.

You don't want to shift so far to the right that you inadvertently overexpose the raw file.

Leave a little empty space on the right end of the histogram.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Exposure Compensation

The exposure compensation feature allows you to shift the exposure setting—plus or minus—brighter or darker.

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When online, exposure compensation is demonstrated.

Do the following.

1) Press and hold the +/– button.

2) A number line will appear or will be highlighted in some way.

Darker   Brighter
-2 -1 0 +1 +2
                       

3) On most digital SLR cameras, turn the knob.

On many point-and-shoot cameras, spin a ring or press a rocker switch.

A plus setting makes the photograph brighter.

A minus setting makes it darker.

4) Release the +/- button.

5) Photograph the scene.

6) Return the exposure compensation back to 0.

Go to Check List.

A Few Canon Cameras

With a few Canon cameras, you have to switch the on/off switch on the back of the camera to the slash icon.

Then, do the following.

1) Fill the frame with the part of the scene that you want to photograph.

2) Turn on the light meter (depress the shutter release slightly).

3) Turn the knob on the back of the camera to adjust the exposure compensation.

Example

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+3.0

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+2.0

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+1.0

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0.0

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-1.0

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-2.0

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-3.0

Which One?

Which of the above exposures is the best?

Let's say you're a book designer.

Long Path

For the cover of a book about the Long Path, a trail that goes from New York City to the Adirondacks, you may select the +2.0 exposure.

That's because the blue trail blaze on the tree looks the best.

All About the Seasons

If you're choosing a photograph for a children's science book about the seasons, you may choose the +1.0 exposure.

The autumn leaves look the best.

Death in Podunk

For a book cover of a mystery book, Death in Podunk, you may choose the darkest, most underexposed exposure.

It's mysterious.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)

Light Meter Vision

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When online, the three settings are displayed above.

Matrix/Evaluative

The light meter measures many locations.

Center Weighted

The light meter measures mostly in the central area.

Spot

The light meter measures a tiny spot in the middle.

You can set what the light meter measures in the frame.

There are three settings.

Setting #1 - Matrix/Evaluative

By default, your camera light meter measures many different locations on the frame (red dots above).

This setting is called Matrix metering (Nikon), Evaluative metering (Canon), or a similar phrase.

Let's say your camera's light meter measures thirty-six locations.

This data is then compared to typical exposure situations stored in your camera's memory.

When there's a match between the data and the stored exposure situations, the light meter knows how to best set the exposure.

Setting #2 - Center Weighted

The second setting is called center-weighted metering (green spot above).

The light in the central area of the frame is measured

Many photographers eschew the technology of Matrix/Evaluative metering for center weighted.

That's because they know what the light meter is measuring—the central part of the frame.

Setting #3 - Spot

Spot metering measures a tiny spot in the middle of the frame (blue spot above).

If you're photographing an eagle's nest with a sky, use spot metering to measure the light from the nest, not the sky.

1 - Richer Color

2 - Eliminate Overexposure

3 - Subject Not Average Toned

4 - Merge Exposures (HDR)

5 - Backlighting

6 - Expose to the Right (Raw)