Treat Your Subject and Background Separately

I ended my last post with a cliffhanger which I promised to resolve nearly two weeks ago, but it was a lot more difficult to write than I originally thought! Is this post worth the wait? I hope it is! So how did I make the second photo look so different from the first? The answer is: I treated my subject and background separately. What does that mean? It means that in the right circumstances you can break up a scene into two parts: the subject and the background, and then treat them differently. Why would you want to do that? Because it creates an image that looks more like what our eyes naturally see. Our eyes are amazing instruments that can see the clouds in a bright sky while simultaneously make out the details under a shady tree. Our digital camera is not as sensitive as our eyes, so our photos often look washed out or too dark. A common situation is when we try to take a photo of someone under the bright sun. In this case, if the subject is perfectly exposed, the sunlit background looks too bright. If we underexpose the background then the subject looks too dark.

Amy looks good, but the sky is too bright.

The sky looks good, but Amy is too dark.

All this sounds great, but it also sounds complicated. Don't worry, it's actually easy to do with a little practice. You first need the right equipment. I can hear you crying, "Oh no! Here's the catch! I need to spend thousands on a fancy camera and lens!" Worry not, because all you need is: 1. A digital camera that allows you to manually control the exposure time (shutter speed), aperture, and hopefully ISO. 2. A flash that lets you control the amount of light it puts out. This flash can be built into the camera or even better, be an external unit. You can use a fancy DSLR or a basic point-and-shoot as long as it meets the criteria above. For you off-camera lighting fans, you'll notice that I didn't stress the requirement that the flash be off the camera. I'll address this in a future post, for now I'm keeping things simple. Ok, you've got the camera and a flash. Now what? Time to treat your subject and background separately. I like to handle the background first, because it's easier to deal with: the background doesn't fidget and it doesn't get grumpy when I fiddle around with my camera's controls. Take a picture of the background and check your camera's LCD. Is it too bright? Too dark? Play with the exposure time, aperture, and ISO until the background looks right. Remember that your shutter speed must not be faster than your camera's maximum flash sync speed (check your camera's manual). I assume that you understand how adjusting the exposure time, aperture, and ISO affects the overall brightness of your image as well as things like depth of field, noise, etc. If you do not understand these terms, look for my series of basic lessons that I'm posting later this month.Exposure: 52.5mm focal length, 1/320 sec, f/14, ISO 100, 3:18pm. Lighting: Just the sun. Now that your background looks nice, it's time to work on your subject. Ask them to stand in the frame and take another shot. One of three scenarios will occur: 1. They look perfect. Great! You're done. 2. They look too dark. You'll need to aim your flash at your subject. Tweak the power of the flash until they look good. 3. They look too bright. This is rarely the case unless you're shooting someone under a spotlight. Most likely your subject is getting blasted by the bright sun. If that's the case, move them to a shadier spot and repeat the process. In my example, Amy looked too dark, so I added a flash. After tweaking the amount of light coming out of the flash, I came up with this shot: Exposure: 52.5mm focal length, 1/320 sec, f/22, ISO 100, 3:36pm. Lighting: Bare flash at 1/2 or full power, unknown zoom, 8:00 camera left, 4 feet away from subject, connected with a wireless remote trigger. You may have noticed that there is 1 1/3 stop difference in aperture between the two shots. In the 18 minutes between photo #1 and #2, I took a lot of shots and I decided I wanted to underexpose the background even more, so I closed down the aperture. I also reframed Amy to remove the barrier cables from the frame and catch the reflection of the sun off of the reservoir. I also lightened her face a bit in Lightroom, because the flash was too powerful. I should have decreased the power of the flash to 1/4. Important note: The subject and the background must be far enough apart from each other that the flash lights only the subject. If they are too close to each other, the flash will affect the background and you won't be able to treat them separately. This won't be easy at first, but with enough practice, this technique will become second nature. The results are worth it! If you want to learn more about how to treat your subject and background separately, read this post from strobist.com, it's far better written. :-)