When you are ready to take more creative control of your camera, it is time to explore the semiautomatic exposure modes, which are Aperture Priority mode and Shutter Priority mode.
In Aperture Priority mode (A or AV on your DSLR dial, depending on the make of your camera), you set the aperture while your DSLR sets the shutter speed based on the ISO setting, in an effort to yield a well-exposed photo.
In Shutter Priority mode (S or TV on your DSLR dial, depending on the make of your camera), you set the shutter speed while the camera sets the aperture size based on the ISO setting, in an effort to create a well-exposed photo. Which mode should you use? That depends on your creative goal and sometimes even on personal preference.
If you wish to control DOF, the area of the photograph that is in focus, choose Aperture Priority mode.
If you want to freeze motion, capture motion progression (referred to as implying motion) or experiment with a special technique called panning (which we’ll talk about soon), you should choose Shutter Priority mode.
You will most likely find yourself shooting with Aperture Priority mode most of the time. Some professional photographers use it all of the time because DOF is of utmost importance to them, even when they are dealing with scenarios where shutter speed is also important (they just keep a close eye on the shutter speed).
These semiauto modes are easiest to use either in overcast daylight or with front lighting during the morning or evening golden hours, as these types of light are soft and even, making it easy to achieve correct exposure.
Always be mindful of your minimum shutter speed and know when it’s time to use camera supports for longer exposures. For a refresher on minimum shutter speed, refer back to Achieving Clear Focus and Sharp Photos previously in this chapter.
As you use each of these semiauto modes and make setting selections, notice what your camera chooses for the other setting. This will help you understand how aperture and shutter speed settings work together to achieve proper exposure, and will make dialing in those settings all by yourself in Manual mode a snap.
You will notice larger apertures yield faster shutter speeds, while smaller apertures yield slower shutter speeds. You will also want to continue to use and master all of the tools/functions you practiced while in P mode like the metering modes, exposure compensation, white balance, AF modes, etc. I must emphasize the importance of you controlling ISO to avoid the visible graininess associated with higher ISO settings.
If you do choose to use auto ISO, just keep an eye on it to make sure it doesn’t get too high. If it does, choose a lower ISO. If the shutter speed gets too slow for a handheld shot, use a support like a tripod. If you don’t have a tripod, go ahead and use the higher ISO to make a handheld shot possible.
Most DSLRs allow you to set a maximum ISO speed in ISO Auto mode (consult your DSLR instruction manual). So if you set the maximum ISO speed to 400, your DSLR won’t ever go above that.
I don’t mean to give the impression that using one of the priority modes is as simple as choosing one setting, allowing the camera to choose the other and snapping away without a worry or care in the world, never checking your settings again. Remember, your DSLR does not have a brain, doesn’t know what your creative goals are and only cares about achieving a proper exposure, no matter the cost. Here’s a little scenario that will show you what I’m talking about and how you can apply some of the information I just tossed at you in the last few paragraphs.
Scenario: Let’s say you’re taking an outdoor portrait using Aperture Priority mode. The sky is blue and bright, with a few big puffy clouds floating around. You head out to the edge of shade with your subject, choosing f/5.6 to blur the background and an ISO speed of 200, which can work well in shade.
Just as you’re about to trip the shutter, one of those big clouds covers up the sun, reducing the available light. You notice your shutter speed is now too slow for a handheld shot. What do you do to get the faster shutter speed you need while you’re still in Aperture Priority mode?
To get the faster shutter speed you need more light. To do that you can choose a wider aperture if possible or raise the ISO.
Doing these things indirectly increases shutter speed, and a combination of the two in low-light situations can be effective. Always attempt to set the ISO as low as possible at all times to keep the noise level low. All of this goes to show that if you’re in the driver’s seat and you know what you’re doing, you can have full manual control of your camera even when you’re in one of the priority modes. Your DSLR is a tool, plain and simple. You’re learning how to control it so you can use it to realize your creative vision. When things get sticky with exposure, some folks prefer to go into full Manual mode to directly control all settings, a valid choice for sure, but there’s definitely more than one way to skin a cat.
Choose Aperture Priority mode when you want to control depth of field (DOF), the portion of your photograph that is clear and in focus.
If you are taking a portrait or still-life photo and wish to have a clear subject in the foreground and a nicely blurred background, you want shallow DOF, which is achieved with a wide aperture (low f-number).
If you are taking a landscape shot and wish to have clarity from foreground to background, you want deep DOF, which is achieved with a small aperture (greater f-number). Let’s say all of the elements in your scene are more or less the same focal distance from you and you want them all in sharp focus. Then it’s best to choose your DSLR’s sharpest aperture, its sweet spot, generally two full stops down from wide open.
OK, quiz time. Do you remember the other two factors that affect DOF? If you answered distance from your subject and focal length, you would be correct. The closer you are to your subject, the shallower the DOF will be, and conversely, the farther away you are from your subject, the greater the DOF will be.
Shorter focal lengths will make the background clearer, while longer ones will make the background more blurry. For a review on aperture and DOF, please refer to the Exposure’s Magic Three section in Chapter One.
With shallow DOF, you will want to pay close attention to focus. If you’re taking a portrait with shallow DOF, make sure you focus on the eyes. For still-life scenes, focus on the object or portion of the object you wish to be clear. You can use Playback mode (zooming in to check the outcome) and retake the photo if necessary, or you can use your DSLR’s handy-dandy DOF preview button.
I am about to share something very important, so be sure to read the next two sentences carefully. When you look through your viewfinder, no matter the aperture setting, your DSLR will always display the image as it appears through a wide-open aperture. That is because the lens stays fully open at its widest aperture and does not physically move to the indicated setting size until you snap the shutter release button.
This is why the DOF preview button is so helpful. When you depress it and look through the viewfinder or on the LCD screen in Live View mode, you will see what the actual photo will look like at the aperture you have chosen. Be aware that the DOF preview button will darken the scene in the viewfinder but not in the actual photograph. It will not darken the scene in Live View mode, but the trade-off is that Live View will suck up your battery life.
Roughly f/4 or wider is a good bet for achieving a soft, blurry background.
Be careful when using very wide apertures for portraits, as the extremely shallow DOF can cause some of the facial features to be blurred, especially at close range. I generally don’t go wider than f/2.8 with portraits for that very reason, unless I want creative blur. Also, avoid using the lock focus/recompose technique with wider apertures because it can lead to blur in your subject. Instead, choose the focus point closest to your subject.
Generally f/5.6 to f/11 is a good range. With these aperture settings, you can capture some of the detail in the background. For group shots use a range of f/8 to f/11 to ensure that all people in the scene are in focus, especially if you have staggering and tiers. For photos where the subjects are on the same plane, use your lens’s sweet spot setting for tack-sharp focus.
Most landscape scenes call for deep DOF where there is clarity from front to back in the scene. A general range of f/11 to f/22 is preferable, with the smaller apertures producing the most clarity from front to back. If you are focusing on a subject in the foreground and want to maintain detail in the background, I recommend using f/18 or f/22. F/16 is also fine if you need to keep the shutter speed from slowing too much.
Higher than f/22 can lead to diffraction, which causes blur. Be aware that using these smaller apertures will mean a slower shutter speed for your camera in order to have enough light to achieve correct exposure. Bring along the tripod just in case, especially during the golden hours, when light is not as bright. If you don’t have your tripod with you and must shoot handheld, it’s time to do some stop swapping in order to get that faster shutter speed. Just enlarge the aperture or increase the ISO to indirectly increase shutter speed. A combination of the two can also be effective.
Depending on the style of your close-up (whether it be more like a miniature landscape scene or a still-life/portrait), you’ll want either greater or shallower DOF. If you want clarity from front to back in your mini-landscape scene, go with a smaller aperture. Note that you will most likely need a tripod or even an external or ring flash (donut-shaped attachable flash unit) to accommodate the smaller aperture. If the macro shot is more like a portrait or still-life scene where you want detail in the background to be blurred, use a wider aperture. Draw from the ranges aforementioned.
Shallow DOF: I captured this moment of my friend and me toasting against a beautiful sunset while camping with our families on Moosehead Lake in Maine. The aperture is set to wide open, creating extremely shallow DOF. 50mm f/1.8 lens, ISO 100, f/1.8 for 1⁄160 sec.
Deep DOF: Hiking to the top of Mount Kineo in Maine offers a stunning, rewarding view. I wanted to capture the girls looking out over the landscape, getting an appreciation for how far they had climbed. To ensure clarity in the scene throughout, I used a small aperture. I bumped up the ISO to keep the shutter speed fast enough to prevent blur, as it was a bit windy up there. Remember that shutter speed slows when you use smaller apertures to allow more light in to correctly expose the photo. 15–85mm f/3.5–5.6 lens at 50mm, ISO 400, f/16 for 1⁄250 sec.
Shutter Priority mode is a good choice when your priority is motion related, whether you want to freeze motion, capture motion progression (implying motion) or use the panning technique where you pan the camera along, level with your moving subject as you take the shot with a slow shutter speed. Important consideration: What happens if you are in Shutter Priority mode and you wish to manipulate aperture? You can indirectly do so by manipulating ISO; increasing ISO yields a smaller aperture, while decreasing it yields a wider aperture.
Here’s another scenario to help demonstrate: Imagine you are photographing a child’s birthday party in late afternoon golden light. The children are jumping up and down on a trampoline bathed in soft, golden front lighting. Behind them is an incredible view of staggered mountains. In Shutter Priority mode you select a fast shutter speed of 1⁄500 sec. to freeze the fast action jumping and an ISO of 200, which is appropriate for the light in the scene. The faster shutter speed automatically generates a wider aperture that blurs the mountains in the background. You want to capture the detail of the mountains in the background and know you need a smaller aperture to do it. How can you get the smaller aperture while maintaining the faster shutter speed for freezing motion? Easy, just increase ISO.
If freezing motion is your aim, you will need a shutter speed of 1⁄250 sec. or faster. Your speed selection would depend on the type of action you are trying to capture. General rules of thumb: The faster the action, the faster the shutter speed needs to be to freeze the motion. Moving in close to your subject, whether you are zooming in with a telephoto lens or physically moving in closer, will require a faster shutter speed than if you are farther away or zooming out.
Freezing Motion - Watching my daughter run and leap through a field of buttercups with flowers in hand melts a mother’s heart. I always wish for her to feel this free. To freeze this moment in time, I set my shutter speed to 1⁄400 sec. while in Shutter Priority mode. 15–85mm f/3.5–5.6 lens at 35mm, ISO 400, f/10 for 1⁄400 sec.
Very slow shutter speeds can capture motion progression characterized by blur. Photographers often refer to this as implying motion. This technique can yield creative shots like the classic, cottony-dreamy blurred waterfall shot, or a capture of commuters in a train station at rush hour where the moving people are blurred and the backdrop of the station is clear and in focus. You might want to use it to photograph a crisp, in-focus subject set against a moving object like a child looking up at a spinning carnival ride. If you want to get really creative, you can imply motion with a still object, where it looks as if the object is actually moving. All of these types of creative shots require slow shutter speeds of 1⁄60 sec. or slower and a tripod is a must.
How slow you are able to make your shutter speed is directly dependent on how bright the scene is and what your aperture and ISO settings are. (The very small apertures and a low ISO will allow for longer shutter speeds.)
The lower the light, the slower the shutter speed you will be able to obtain. If the scene is too bright, you can darken the lens with an ND filter so less light will hit your image sensor, allowing for the slower shutter speed (more details on ND filters coming right up).
Don’t feel locked in by the slow shutter speed suggestions below. Experiment to find your own preferences, in conjunction with what the ambient light (available light) in your scene will allow. Your distance from the subject also makes a difference. The closer you are to your subject, whether you are zooming in or physically moving closer, the blurrier the subject will be.
Implying Motion - I’m always on the lookout for pretty waterfalls, and I don’t think I’ll ever tire of those timeless, dreamy, cotton-candy-like captures of them. I made this shot with a slow shutter speed, using a bridge railing as a support, and used my camera’s self-timer to avoid shaking the camera by pressing the button myself. In Aperture Priority mode, I set the ISO to 100 so the image sensor would be less sensitive to the light, chose a small aperture of f/22, and since the environment was pretty bright I attached a 0.6 neutral density (ND) filter to my lens to reduce the amount of light passing through it, allowing for the slower shutter speed. You can certainly use Shutter Priority mode with these types of shots and experiment with different shutter speed settings. (If the camera can’t handle the slower shutter speed you selected, it will blink to let you know.) You can also take slow shutter speed shots in Manual mode, and I’ll show you how when we get to that point in the book. 15–85mm f/3.5–5.6 lens at 85mm, ISO 100, f/22 for 0.6 sec.
Panning - With my camera set to a slow shutter speed, I panned along with my son on his bike, shooting in Continuous Shooting mode (Burst mode). The result is a clear, in-focus subject in motion set against a blurred background, which enhances the feeling of the motion. 15–85mm f/3.5–5.6 lens at 17mm, ISO 100, f/3.5 for 1⁄64 sec.
Panning is a slow shutter speed technique where the photographer pans along with her subject, parallel to it, while snapping away in Continuous Shooting mode (Burst mode). The resulting photo yields a clear, crisp subject set against a blurred, whirling smear of a background. Panning shots portray a feeling of forward motion and energy.
Now that you are exploring the semiauto modes and gaining further creative control of your DSLR, it’s time to introduce you to yet another tool that will help you with tricky exposure situations—AE lock. Use the Auto Exposure (AE) lock button if the area you wish to focus on is different than the area you want to meter off of.
Let’s say, for example, that my scene has a rocky Maine coastline in the foreground and middle ground, with a gray cottage high on top of a hill in the background, set against a cloudy/overcast, fairly bright morning sky. If I lock focus on the house in Evaluative Metering mode (using One Shot focus mode) and take the photo, the rock outcroppings will turn out underexposed. Why? Because my camera metered (and properly exposed) the brighter part of the scene and not the darker rocks.
Here’s where AE lock comes in handy. It allows me to meter off the rocks so they will be correctly exposed, lock that exposure setting, and then focus on the house and take the shot.
I meter off the rocks by locking focus/exposure on them, depressing the shutter button halfway. While the shutter button is depressed halfway, I then press the AE lock button on the back of the camera to lock exposure settings. I can then let go of both the AE lock button and the shutter button, and AE lock will still be activated.
I am now free to take a brand-new shot where I lock focus on the cottage by depressing the shutter button halfway, recompose if necessary with the button still depressed halfway and then take the photo. Note: Your DSLR should be able to use this technique with any AF point.
AE Lock Button - In Aperture Priority mode, I used my AE lock button so I could meter off the coastal rocks and then focus on the cottage. I processed this photo in Photoshop afterwards, adding a sepia tint. 15–85mm f/3.5–5.6 lens at 15mm, ISO 200, f/16 for 1⁄200 sec.
The AE lock feature will disengage on its own a few seconds after taking the shot. If you want to maintain the exposure lock and take more photos in the same setting, you will have to keep the AE lock button depressed while you take the shots. Double-check your camera instruction manual for specifics on how the AE lock feature works with your camera. There is a small trade-off in this photo scenario, which you may have already guessed. Because I have metered off the rocks, the cottage and the sky will appear a bit brighter than I wish. There are actually tools for dealing with this kind of exposure problem.
I could use a bracketing technique where I take several different exposures of the same shot and combine them in a software program like Photoshop CS to produce a perfectly exposed shot, known as High Dynamic Range imaging or HDR photography. I could also use what’s called a graduated neutral density (ND) filter, which attaches to my camera lens. Half of this type of ND filter is darkened, while the other half is not; just place the darker part of the filter where the sky will be.
Important note: Although I find it fairly easy to use the AE lock button, be aware that some photographers would prefer to meter off the rocks, remember the settings, go into Manual mode and dial in those settings, then take the photograph. Or if a photographer shoots purely in Manual mode, she would meter off the rocks, use those settings for the shot, recompose and then take the shot. It’s really a matter of preference. I’m a flutist, so pressing multiple buttons to get the shot is no biggie.
Earlier we talked about using Spot Metering mode when taking portraits with backlighting so that the camera meters off the person, thus properly exposing her despite the backlight. To get the best exposure, I recommend metering off the brightest part of the subject’s face. Remember that you want to focus on the eyes.
So, how can one both meter off the brightest part of the face and focus on the eyes? Here’s where AE lock comes in handy. You can meter off the brightest part of the face and press the AE lock button to lock exposure settings. Then take the shot as you normally would, aiming the center focus point at the eyes and locking focus by depressing the button halfway again, recomposing slightly if you wish with the shutter button still depressed halfway, then taking the shot. Note: If you have a Nikon or pricey Canon, you should be able to use Spot Metering mode successfully with any AF point. With most Canons, spot metering is fixed to the center of the viewfinder, so it’s easiest to spot meter with the center AF point. If you want to use another AF point, it’s a little tricky but possible. First select your desired AF point, then place the center of the frame over the spot you want to meter off. Depress the AE lock button to lock exposure. Now you are free to focus using your desired AF point and to take the photo!
Be sure to reset your camera settings with each new scenario. You might need to change the white balance setting, choose another AF point, readjust exposure compensation, select another metering mode, etc. Countless times I’ve accidentally shot with previously used settings that just didn’t work with the new scenario.
I hear a drumroll. It’s leading us straight to Manual mode, because if you’ve been working hard on all of the skills in Chapters One and Two thus far, you are now ready to take that step!