Mostly what prompted this post is that I've been questioned a few times recently when I am posing people with their back to the sun. It's understandable. I, too, grew up often looking into the sun with squinting, watering eyes when people took my picture. I think it's a common idea that we need to face people toward the sun to get enough light. I've certainly used that method myself. Exhibit A:
Backlighting is trendy, but it also makes a lot of sense in certain situations. Here's what I love about it:
You can also see that in the photo on the left, her hair and the background don't have much separation in the darker spots. If I had her against a more solidly dark background, she would sort of blend in so that you would barely know where her hair ended and the background began. On the right you have a definite outline to help her pop out from the background.
Backlighting a subject does take a bit of practice. You have to get to know the right circumstances that will give you the look you're after. Here are a few tips in the form of a diagram I made:
1. Look for a background that helps filter the sunshine for a pleasing look. If you just have sky behind the person, it'll be very washed out (assuming you are exposing for the face, not the background). Sometimes that's okay! But just know that in case that's not the look you're after.
If your background doesn't allow any light to filter through or around it, you're basically just photographing your subject in the shade. That is also fine, but it means you probably won't get the rim lighting or glowy feel.
2. Make sure you are in manual mode on your camera so you can control the exposure. If you just let your camera handle it, it's going compensate for the brightness of the sun in the background and give you an underexposed photo. You need to force it to let in more light so the faces of your subjects are nice and bright. This is also what washes out the background to give it a more dreamy appearance.
3. It really helps when there is a pale scene/surface behind you to reflect a bit of light back to your subject. It means the background will be less washed out to include a bit more detail. Honestly, this is not always something I seek out, but you'll start noticing spots that work better because of the reflective surfaces. Some are even overly reflective, and you can still have squinting even when the person's back is to the sun. It's all a balance that just takes experience. I certainly need more experience! Meanwhile, it's really fun to discover awesomely-lit locations to place a subject. Sometimes you get lucky and it's easy, other times you have to keep moving to find a better spot. You can start practicing by simply asking your subject to turn their back to the sun, and start taking some pictures. You'll begin to see what works and what doesn't.