Now let's say you're out at sunset. You're ready. You're going to get a sunset image that rivals anything you've ever seen on Flickr, Pinterest or National Geographic.
Under the Docks in California by Flickr user Stuck in Customs
You've read the first few articles of the Dash so you know that slightly underexposing is a good idea. You set up your camera, you meter the scene, and you subtract a little light with your exposure compensation setting. You take the shot. Awesome! You check your LCD. Great. Then you go home and open up the shot on your computer … and … you're disappointed.
Underexposing a sunset is a creative choice—but what if you wanted just a little bit more detail in that water? Bracketing can help ensure that you always have a few good exposures to choose from.Charles River by Flickr user CoreForce
Well, a lot of things might have happened, and it may be hard to pinpoint what exactly went wrong. But the bottom line is, your camera's meter doesn't really know what to do with a sunset. It can't read your mind, so it didn't know that you wanted a darker sky, or a brighter one, or more detail in those trees. The only reference point it has to go by is the one that it's been programmed for: 18 percent gray, 18 percent gray, 18 percent gray.
Now once you get very good at judging light (and you will, with practice), you'll be able to make a pretty good guess at what settings you'll need to recreate a sunset in exactly the way you've imagined it. You can improve your odds by using your spot meter to make a better guess at what the right exposure might be. But even then, it's a good idea to take some additional steps to make sure that you get the very best exposure, just in case the one you thought was the right one turns out to be less than perfect. And how do you do that? You bracket.
What is bracketing?
Bracketing is an extremely simple concept, made even simpler by your DSLR's advanced capabilities. Bracketing simply means that you take one shot where you think the exposure ought to be, and then one a stop or a half stop below, and one a stop or half stop above. Now you have three images to choose from, and there's a much greater chance that one of those is going to make you happy.
Auto Exposure Bracketing
Depending on your camera, bracketing can either be done manually or automatically.
Most DSLRs have a "bracketing" function that will do this for you automatically. This setting is usually called Automatic Exposure Bracketing or "AEB." In most cameras, the AEB setting is configurable—you'll be able to specify the number of stops between each exposure as well as the number of shots you want to bracket (if you're not sure what I mean here, check the next section on manual bracketing). Any limitations are going to be specific to your particular camera model, though, as will instructions on how to access and configure this setting. So while I do hate to say things like "refer to your manual" (it's so impersonal), I will have to tell you to do that in this case because there's a lot of variability to the way this setting works from one camera to another. But the benefit to using AEB is that once you have it configured the way you want, you don't have to muck around with your settings and miss something in the failing light. You can just concentrate on composition rather than worrying too much about your settings.
Which one would you choose? Each of these shots was taken with the same f-stop and ISO, but they were bracketed, which means the photographer took the same shot at different shutter speeds. As a result the texture and detail in the sky is very different from one image to the next.
To bracket manually, put your camera in manual mode, then look through your viewfinder. You'll see that gauge inside that tells you how good your camera thinks your exposure is going to be. When the needle is on the "0," your camera thinks you've got the correct exposure. When it's somewhere between the "0" and the "-," it thinks you're underexposing. When it's somewhere between the "0" and the "+," it's pretty sure you're going to have an overexposed picture. Now, it may or may not be right, but you can use this gauge to judge where you should bracket your shots.
First, dial in the settings that you think are correct for the scene. You may be using a reading from your spot meter, or just your own judgement to arrive at this conclusion. Take the shot and review the image on your LCD. Remember that your LCD doesn't really give you the best way to judge your exposure. It's a small image, so it may look good even though it's not going to impress you at full resolution. But it will tell you whether you are in the general ballpark, or if you're way off. If you're way off, adjust and reshoot. But if the exposure looks pretty good, you can start bracketing.
Look through your viewfinder again and see where that needle is pointing. Now change your settings so you're a third or a half stop under where the needle originally was. Take the shot. Now change your settings in the opposite direction, so you're a third or a half stop over that original position. Take another shot.
If you don't have limited memory card space, take more than just three shots—adjust your exposure by 1/3rd of a stop and take several at 1/3rd increments in both the "-" and "+" directions. You may end up with a lot of really unusable images that way, but your chances of hitting on that perfect exposure are going to be much higher. Digital frames are free, so you really don't have any reason not to do this—it only takes a few seconds and is infinitely better than missing that perfect shot because you didn't take enough photos.
Sorrow by Flickr user Christolakis
Don't be afraid to try as many different exposures as you can fit into that one beautiful sunset. A beautiful composition combined with generous bracketing can almost not fail to produce a stunning image.