Understanding how exposure works in the camera

Your D780 exposes images the same way film cameras did. Light enters the camera through the lens and is recorded on the sensor. The amount of time the shutter is open and the amount of light entering the camera determines whether the resulting image is too dark, too bright, or properly exposed.

The duration of the exposure is the shutter speed. Your camera has a shutter speed range from as long as 30 seconds to as fast as 1/8000 second. A fast shutter speed stops action, and a slow shutter speed leaves the shutter open for a long time to record images in low-light situations. You can also use a slow shutter speeds for special effects.

You can increase the shutter speed up to 900 seconds (15 minutes) if you specify this duration in the d6: Extended Shutter Speeds (M) area of the Custom Settings menu.

The aperture is the opening in the lens that lets light into the camera when the shutter opens. You can change the aperture diameter to let in a lot of light or a little light. The f-stop value determines the size of the aperture. A low f-stop value (large aperture) lets a lot of light into the camera, and a high f-stop value (small aperture) lets a small amount of light into the camera. Depending on the lens you’re using, the f-stop range can be from f/1.2, which sends huge gobs of light into the camera, to f/32, which lets a miniscule splash of light into the camera. The f-stop also determines the depth of field, a concept I explain in “Controlling depth of field,” later in this chapter.

The duration of the exposure (shutter speed) and aperture (f-stop value) combination determines the exposure. For each lighting scenario you encounter, several different combinations render a perfectly exposed photograph. Use different combinations for different types of photography. The camera’s metering device examines the scene and determines which shutter speed and f-stop combination will yield a properly exposed image. The camera can choose a fast shutter speed and large aperture, or a slow shutter speed and small aperture.

Choosing a metering mode

The metering mode you choose depends on your subject matter. You may choose one metering mode for photographing landscapes and architecture, another mode for photographing bright subjects surrounding by darkness (for example, a singer in a stage spotlight), and yet another metering mode for scenes with bright highlights.

To set the camera metering mode, follow these steps:

1. Press and hold the zoom out/metering button (see Figure 9-3).

2. Rotate the main command dial to choose one of the following options:

   • Matrix metering: Use this metering mode to create natural-looking images when the scene you’re photographing is evenly lit. This metering mode is great for photographing landscapes and architecture.
   • Center-weighted metering: Use this metering mode when your center of interest is in the middle of the frame.

     

   • Spot metering: This metering mode meters a small area of the frame. Use this metering mode when your subject is brighter or darker than the background, to properly expose your subject.
   • Highlight-weighted metering: Use this metering mode when you need to preserve detail in the highlights (for example, when photographing a singer illuminated by spotlights on a stage).

   The metering mode is displayed in the viewfinder and on the control panel. Figure 9-4 shows the icons for the different metering modes.

3. Release the zoom out/metering button.

   You’re ready to create images with the specified metering mode.

   

In most instances, matrix metering should be your go-to mode. If upon reviewing an image, the results are unsatisfactory, switch to a different metering mode.

You can also choose a metering mode using the still photography i menu. I discuss the still photography i menu in the “Using the Still Photography i Menu” section of this chapter.

Using programmed auto (P) mode

When you take pictures with the programmed auto (P) mode, the camera determines the shutter speed and aperture (f-stop value) that yields a properly exposed image for the lighting conditions. This may sound identical to Auto mode, but P mode, you can change the shutter speed and aperture to suit the scene or subject you’re photographing.

To take pictures in programmed auto (P) mode, follow these steps:

1. Press the mode dial lock release and then rotate the mode dial to P (see Figure 9-10).

2. Press the ISO button and rotate the main command dial to change the ISO sensitivity to the desired setting.

   A higher ISO makes the camera’s sensor more sensitive to light, which is ideal when you’re photographing in dim light or at night. For more information on changing the ISO, turn to Chapter 10.

3. Press the shutter-release button halfway to achieve focus.

   The white dot on the left side of the viewfinder appears when the camera achieves focus. If you see a flashing right or left arrow, the camera can’t achieve focus and you must manually focus the camera.

   

4. Check the shutter speed and aperture.

   You can use the viewfinder or tilting control panel (see Figure 9-11) to check the shutter speed and aperture. If the combination will cause the image to be overexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the right of center. If the image is underexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the left of center.

   

5. Press the shutter-release button fully to take the picture.

   The image displays almost immediately on your tilting monitor.

You can shift the exposure and choose a different shutter speed and aperture combination. Use this option when you want to shoot with a faster shutter speed to freeze action or a different aperture to control depth of field. This is known as flexible program mode. To shift the flexible program mode, follow these steps:

1. Follow Steps 1 through 3 of the preceding instructions and then press the shutter-release button halfway.

   The camera achieves focus.

2. Rotate the main command dial.

   As you rotate the dial, different shutter speed and aperture combinations appear on the control panel and in the viewfinder. If you’re trying to freeze a fast-moving object, rotate the main command dial until a fast shutter speed appears. If depth of field is your goal, rotate the main command dial until a large aperture (low f-stop value) appears for a shallow depth of field, or until a small aperture (high f-stop value) appears for a large depth of field.

3. When you see the desired combination of shutter speed and aperture, press the shutter-release button fully to take the picture.

   The image appears almost immediately on your tilting monitor.

Using aperture-priority auto (A) mode

If you like to photograph landscapes, aperture-priority auto (A) mode is right up your alley. When you take pictures using aperture-priority auto (A) mode, you choose the desired f-stop and the camera supplies the correct shutter speed to achieve a properly exposed image. A large aperture (small f-stop value) lets a lot of light into the camera, and a small aperture (large f-stop value) lets a small amount of light into the camera. The benefit of shooting in A mode is that you have complete control over the depth of field (see “Controlling depth of field,” later in this chapter). You also have access to all the other options, such as setting the ISO, choosing a Picture Control when shooting in JPEG mode, choosing an AF mode or a release mode, and so on.

To take pictures with aperture-priority auto (A) mode, follow these steps:

1. Press the mode dial lock release and then rotate the mode dial to A (see Figure 9-12).

2. Press the ISO button and then rotate the main command dial to change the ISO to the desired setting.

   A higher ISO makes the camera sensor more sensitive to light, which is ideal when you’re photographing in dim light or at night. For more information on changing ISO, see Chapter 10.

3. Rotate the sub-command dial to select the desired f-stop.

   As you change the aperture, the camera calculates the proper shutter speed to achieve a properly exposed image. The change appears on the control panel and in the viewfinder. As you rotate the main command dial, monitor the shutter speed in the viewfinder (see Figure 9-13). If the combination will cause the image to be overexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the right of center. If the image is underexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the left of center.

   

   

4. Press the shutter-release button halfway to achieve focus.

   A white dot appears in the viewfinder when the camera achieves focus.

5. Press the shutter-release button fully to take the picture.

   The image appears on your tilting monitor almost immediately.

Controlling depth of field

Depth of field is how much of your image looks sharp and is in apparent focus in front of and behind your subject. When you’re taking pictures of landscapes on a bright sunny day, you likely want a depth of field that produces an image in which you can see the details for miles and miles…. If you’re taking portraits, where the person matters more than what’s in front of or behind her, you want to have a very shallow depth of field in which your subject is in sharp focus but the foreground and background are a pleasant out-of-focus blur.

You control the depth of field in an image by selecting the f-stop in aperture-priority auto (A) mode and letting the camera do the math to determine which shutter speed will yield a properly exposed image. You get a limited depth of field when using a small f-stop value (large aperture), which lets a lot of light into the camera. A fast lens with a smaller aperture lets you shoot at a faster shutter speed. A fast lens:

• Has an f-stop value of f/2.8 or smaller
• Gives you the capability to shoot in low-light conditions
• Gives you a wonderfully shallow depth of field

When shooting at a lens’s smallest f-stop value, you’re letting the most amount of light into the camera, which is known as shooting “wide open.” The lens you use also determines how large the depth of field will be for a given f-stop. At the same f-stop, a wide-angle lens has a greater depth of field than a telephoto lens does. When you’re photographing a landscape, the ideal recipe is a wide-angle lens and a small aperture (large f-stop value). When you’re shooting a portrait of someone, you want a shallow depth of field. Therefore, a telephoto lens with a focal length that is 85mm to 120mm with a large aperture (small f-stop value) is the ideal solution.

Figure 9-14 shows two pictures of the same subject. The first image was shot with an exposure of 1/640 second at f/1.8, and the second image was shot with an exposure of 1/80 second at f/10. In both cases, I focused on the subject. Notice how much more of the image shot at f/10 is in focus. The detail of the flowers in the second shot distracts the viewer’s attention from the subject. The first image has a shallow depth of field that draws the viewer’s attention to the subject.

Using depth-of-field preview

When you compose a scene through your viewfinder, the camera aperture is wide open, which means you have no idea how much depth of field you’ll have in the resulting image. You can preview the depth of field for a selected f-stop by pressing the Pv button on your camera, which closes the aperture to the f-stop you use to take the picture.

To preview depth of field, follow these steps:

1. Compose the picture and choose the desired f-stop in aperture-priority auto (A) mode.

   See “Using aperture-priority auto (A) mode,” earlier in this chapter if you need help.

2. Press the shutter-release button halfway to achieve focus.

   A white dot appears on the left side of the viewfinder when the camera focuses on your subject.

3. Press the Pv button (see Figure 9-15).

   The button is conveniently located on the front right side of the camera near the sub-command dial when your camera is pointed toward your subject. You can easily locate the button by feel.

   When you press the button, the image in the viewfinder may become dim, especially when you’re using a small aperture (large f-stop number) that doesn’t let a lot of light into the camera. Don’t worry — the camera chooses the proper shutter speed to compensate for the f-stop you select, resulting in a perfectly exposed image.

When you use depth-of-field preview, pay attention to how much of the image is in apparent focus in front of and behind your subject. To see what the depth of field looks like with different f-stops, select what you think is the optimal f-stop for the scene you’re photographing. Then press the shutter-release button halfway to achieve focus, as I outline earlier, and then rotate the main command dial to choose different f-stop values.

As long as you hold down the Pv button while you’re choosing different f-stops, you can see the effect each f-stop has on the depth of field. I know, it’s a bit of a juggling act, but given some practice, you’ll get the hang of it. The alternative is to take several pictures of the subject with different f-stops and keep the one you like best.

Using shutter-priority auto (S) mode

When your goal is to accentuate an object’s motion, choose shutter-priority auto (S) mode. When you take pictures in shutter-priority auto (S) mode, you choose the shutter speed and the camera supplies the proper f-stop value to properly expose the scene. Your camera has a shutter speed range from 30 seconds to 1/8000 second. When you choose a slow shutter speed, the shutter is open for a long time. When you choose a fast shutter speed, the shutter is open for a short duration and you can freeze action.

You can increase the shutter speed up to 900 seconds (15 minutes) if you specify this duration in the d6: Extended Shutter Speeds (M) area of the Custom Settings menu.

To take pictures in shutter-priority auto (S) mode, follow these steps:

1. Press the mode dial lock release and then rotate the mode dial to S (see Figure 9-16).

2. Rotate the main command dial to choose the desired shutter speed.

   As you change the shutter speed, the camera determines the proper f-stop to achieve a properly exposed image. If you notice that the shutter speed is too slow for a blur-free picture, you have to put the camera on a tripod or increase the ISO sensitivity setting. If the combination of shutter speed and aperture will cause the image to be overexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the right of center. If the image is underexposed, the exposure indicator on the control panel and in the viewfinder will show a vertical line to the left of center.

3. Press the ISO button and then rotate the main command dial to change the ISO to the desired setting.

   Choose an ISO that enables you to achieve the desired shutter speed. For more information on changing ISO, see Chapter 10.

4. Press the shutter-release button halfway to achieve focus.

   A white dot appears in the left side of the viewfinder. If you see a flashing left or right arrow, the camera can’t achieve focus. If this occurs, switch the lens to manual focus and twist the focusing barrel until your subject snaps into focus. Figure 9-17 shows the viewfinder when working in shutter-priority auto (S) mode.

5. Press the shutter-release button fully to take the picture.

   The image appears on your tilting monitor almost immediately.

Shutter-priority auto (S) mode is the way to go whenever you need to stop action or show the grace of an athlete in motion. You’d use shutter-priority auto (S) mode in lots of scenarios. Figure 9-18 shows the effects you can achieve with different shutter speeds. The image on the left was photographed with a slow shutter speed, and the image on the right was photographed with a fast shutter speed to freeze the action. For more information on using shutter-priority auto (S) mode when photographing sporting events, check out Chapter 13.

Using manual (M) mode

You can also manually expose your images. When you choose manual (M) mode, you supply the f-stop value and the shutter speed. You can choose from several combinations to properly expose the image for the lighting conditions. Your camera meter gives you some assistance to select the right f-stop and shutter speed combination to properly expose the image. (For a refresher on how your camera determines exposure, check out “Understanding how exposure works in the camera” earlier in this chapter.)

To manually expose your images, follow these steps:

1. Press the mode dial lock release button and then rotate the mode dial to M (see Figure 9-19).

   

2. Rotate the main command dial to set the shutter speed.

   The shutter speed determines how long the shutter stays open. A slow shutter speed is perfect for a scene with low light. A fast shutter speed freezes action. As you change the shutter speed, review the exposure indicator on the control panel or, if you have the shutter-release button pressed halfway, in the viewfinder.

   When the exposure is correct for the lighting conditions, the exposure level mark aligns with the center of the scale. Figure 9-20 shows the exposure indicator as seen in the control panel. If the exposure level mark is to the right of center, the image will be overexposed. If the exposure level mark is to the left of center, the image will be underexposed. Of course, you’re in control. You may want to intentionally overexpose or underexpose for special effects. For example, if you slightly underexpose the image, the colors will be more saturated. You can also monitor exposure in the viewfinder using the scale on the right side of the viewfinder.

3. Rotate the sub-command dial to set the f-stop value.

   The f-stop value determines how much light enters the camera. A small f-stop value, such as f/2.8, lets a lot of light into the camera and also gives you a shallow depth of field. A large f-stop value lets a small amount of light into the camera and gives you a large depth of field. As you change the f-stop value, review the exposure indicator on the control panel or, if you have the shutter-release button pressed halfway, in the viewfinder. When the exposure is correct for the lighting conditions, the exposure level mark aligns with the center of the scale. If the exposure level mark is to the right of the center, the image will be overexposed. If the exposure level mark is to the left of center, the image will be underexposed.

4. Press the shutter-release button halfway to achieve focus.

   A white dot appears in the left side of the viewfinder when the camera has achieved focus. If you see a flashing left and right arrow, the camera cannot achieve focus and must be focused manually.

5. Press the shutter-release button fully to take the picture.

   

Introducing EFCT mode

There’s one setting on the mode dial that may leave you scratching your head, especially if you’ve never used a Nikon camera before, and that’s the EFCT mode (known as Effects on older Nikon cameras). The EFCT mode is only available when you shoot in JPEG format. But if you like to create special effects quickly, the EFCT mode is for you.

For example, if you want to create a picture that looks like a graphic illustration, you’ll find a mode that suits your creative bent after rotating the mode dial to EFCT. I show you how to create images using the EFCT mode in Chapter 12.

Shooting long exposures

When you want to create a long exposure, you have two options: a time exposure or a bulb exposure. You create long exposures while shooting in manual (M) mode. Follow these steps:

1. Mount the camera on a tripod.

2. Compose the image and focus the camera.

   You can use manual focus or use a single AF point for focus. If you use the single AF point, press the shutter-release button halfway to achieve focus. When focus is achieved, continue to hold the shutter-release button halfway and then rotate the focus selector lock to L to lock the focus before removing your finger from the shutter-release button.

3. Place the eyepiece cap over the eyepiece.

   This prevents stray light from reaching the sensor through the eyepiece.

4. Press and hold the mode dial lock release and rotate the mode dial to M (see Figure 9-21).

5. Rotate the main command dial to select one of the following options: bulb or time.

   Rotate the dial until you see bulb or time (designated by --) on the control panel. The image on the left in Figure 9-22 shows the control panel when shooting a bulb exposure, and the image on the right shows the control panel when shooting a time exposure.

   

   

6. Release the shutter.

   If you choose bulb, the shutter releases when you press the shutter-release button. When shooting bulb, you hold the shutter open until the exposure is complete.

   If you choose time, the shutter releases when you press and release the shutter-release button.

7. Close the shutter.

   If you choose bulb, the shutter closes when you take your finger off the shutter-release button.

   If you choose time, the shutter closes when you press the shutter-release button a second time.

If you’re shooting long exposures without a remote release, time is your best option. Use the self-timer to delay the release of the shutter to minimize any operator-induced blur. When you release the shutter to end the exposure, press the shutter-release button gently.

Figure 9-23 shows you the type of photograph you can create when shooting a long exposure with the bulb or time shutter option. This image is a 15-second time exposure. Notice the headlight and taillight trails.

When shooting long exposures, I recommend you use a remote release to open and close the shutter.

By default, the longest exposure your D780 can capture is 30 seconds when shooting bulb or time. However, you can increase this by using the d6: Extended Shutter Speeds (M) option from the Custom Settings menu. You can increase the maximum exposure to 60 seconds, 90 seconds, 120 seconds, 180 seconds, 240 seconds, 300 seconds, 480 seconds, 600 seconds, 720 seconds, or 900 seconds.

Enabling long-exposure noise reduction

When you shoot long exposures, digital noise is a fact of life. If the images you capture using long exposures have areas of dark shadows, the noise is most noticeable in that tonal range. You may also notice areas of fog and bright lights in images captured with long exposures.

You can reduce this problem by following these steps:

1. Press the MENU button.

   The camera menus appear on the tilting monitor.

2. Press the down arrow on the multi selector to select the Photo Shooting menu, and then press the left arrow on the multi selector to highlight the icon.
3. Press the down arrow on the multi selector to highlight Long Exposure NR (see Figure 9-24).

4. Press the right arrow on the multi selector.

   The long-exposure noise reduction options appear on the tilting monitor (see Figure 9-25).

5. Press the down arrow on the multi selector to highlight On, and then press OK.

   Long-exposure noise reduction will be applied to image captures with long exposures.

Long-exposure noise reduction is applied after you release the shutter. This takes some time, roughly double the time it normally takes to process an image. While the image is processing, you see Job nr flashing on the control panel and in the viewfinder. You won’t be able to take additional pictures until the processing is complete. If you turn off the camera before the processing is finished, the image will be saved but noise reduction won’t be applied.

Using exposure compensation

When your camera gets the exposure right, it’s a wonderful thing. Sometimes, however, the camera doesn’t get it right. When you review an image on the camera’s tilting monitor and it’s not exposed to suit your taste, you can compensate manually by increasing or decreasing exposure.

To manually compensate for camera exposure, follow these steps:

1. Press the mode dial lock release, and choose P, A, or S from the mode dial (see Figure 9-26).

   Exposure compensation is available only when you take pictures in programmed auto (P) mode, aperture-priority auto (A) mode, or shutter-priority auto (S) mode.

2. Press the shutter-release button halfway.

   The camera meters the scene.

3. Press the exposure compensation button (see Figure 9-27) and rotate the main command dial while looking in the viewfinder or at the control panel.

   Rotate the dial clockwise to decrease exposure or counterclockwise to increase exposure. As you rotate the dial, you see the exposure indicator in the viewfinder and on the control panel move, which shows you the amount of exposure compensation you’re applying (see Figure 9-28).

4. Press the shutter-release button fully to take the picture.

5. To cancel exposure compensation, press and hold the exposure compensation button, and then rotate the main command dial until the exposure indicator is in the center of the exposure compensation scale.

   You see the exposure compensation scale in the viewfinder and on the control panel.

Bracketing exposure

When you’re photographing an important event, properly exposed images are a must. Many photographers get lazy and don’t feel they need to get it right in the camera when they have programs like Adobe Photoshop or Adobe Lightroom. But you get much better results when you process an image that’s been exposed correctly. Professional photographers bracket their exposures when they photograph important events or places they may never visit again.

When you bracket an exposure, you take at least three pictures: one with the exposure as metered by the camera, one with exposure that’s been decreased, and one with exposure that’s been increased. You can bracket up to ±15 exposure value (EV) in ⅓ EV increments. Bracketing is only available in P, A, S, or M modes. You can also determine the number of frames that are bracketed.

To bracket your exposures, follow these steps:

1. Press and hold the BKT button on the left side of the camera when pointed toward your subject (see Figure 9-29) and then rotate the main command dial to specify the number of images in the bracketing sequence.

   As you rotate the dial, the number of frames appears on the control panel.

2. Press and hold the BKT button, and then rotate the sub-command dial to specify the bracketing increment.

   Each time you rotate the dial, you increase the increment by ⅓ EV. If you choose an EV of 2 or 3, the maximum number of shots is 5. If you specify 7 or 9 in Step 1, the number of exposures is automatically set to 5. The number of frames and EV brackets are displayed on the control panel, and BKT appears in the viewfinder (see Figure 9-30).

3. Compose the image and press the shutter-release button halfway.

   A white dot appears on the left side of the viewfinder when focus is achieved.

   

   

4. Press the shutter-release button fully.

   The camera creates the number of images specified. For example, if you bracket five frames, the camera captures one image with standard exposure, two images with decreased exposure, and two images with increased exposure.

To determine the start of a bracketing sequence, place your hand in front of the lens and take a picture before you take the first picture in the sequence. Do the same after you capture the last image for the bracketing sequence. When you edit the images, the photo of your hand designates the start and end of the sequence, which is useful if you’re using the image sequence to create a high dynamic range (HDR) image using third-party software.

Most third-party image-editing software will automatically align a set of bracketed exposures when merging them to an HDR image. However, for the best results, I recommend you place the camera on a tripod when bracketing exposure.

You can use Custom Menu Settings b1: EV Steps for Exposure Cntrl to change the EV value of each image bracketed from the default ⅓ EV to higher values. I recommend you stick with the default ⅓ EV, though, and not visit this option.

Locking focus and exposure

You can also lock focus and exposure on a specific part of the frame, which is handy when you want a specific part of the frame exposed correctly. For example, recently I was photographing a beautiful sunset. The camera meter averaged the exposure for the scene, and the image ended up with blown-out highlights around the sun and clouds that weren’t as dark and colorful as I saw them. To compensate for this, I locked exposure on the blue sky, and the picture turned out perfectly.

To lock exposure, follow these steps:

1. Press the AF-mode button (see Figure 9-31), rotate the main command dial, and choose AF-S.

   Your camera now has a single autofocus point in the middle of the frame.

2. Use the multi selector to move the autofocus point over the area of the frame where you want to lock focus and exposure.

   

3. Press the AE-L/AF-L button (see Figure 9-32).

   The AE-L icon appears in the viewfinder.

4. Press the shutter-release button halfway to achieve focus.

   A white dot in the viewfinder tells you that the camera has achieved focus.

5. Press the shutter-release button fully to take the picture.