Understanding Backlight and Silhouettes
We all grew up from a young age, hearing, this one photography rule, "Always keep the sun at your back" or, "Don't shoot directly into the light!" We all also learned, there are exceptions to every rule, and these are two shooting styles that intentionally break this rule: silhouette and backlight.
Everyone knows some iconic silhouette shots: a fisherman on the beach, against a sunset or a girl outlined in front of a lace covered window. Shooting a silhouette is a technique that involves framing your shot so that the light is directly behind your subject, creating a solid dark outline shape against a lighter background.
Backlighting is a photography term for any image taken with the plane of the subject between the camera and the dominant light source. The backlight can be anywhere behind, including slightly off to the side and behind. Backlighting refers to images where some light and detail is visible on the front of the subject, as opposed to silhouette, which is a solid, black outline.
The example lighting diagram above shows the setup used for a typical silhouette shot.
Place your subject between the camera and a bright light source. Above, we have the Sun, outside a window, and then the subject, and the camera. We set exposure based on the brightest part of the image: the window, and not set exposure for the subject. Since the window is so much brighter than the subject, this means that the subject will be underexposed, giving a nice, dark silhouetted subject.
The keys to shooting a silhouette is to find a strong light, like the sunset, or a window in a darker room. Focus your shot on the subject, compose along the rule of thirds and set the image exposure for the background light.
A well done backlit image is a bit more difficult to do. It's somewhere between a nice silhouette, and a nicely exposed front lit image. IN our lighting diagram above, we have the background, a flash head on tripod facing the subject, a flash head facing the background, the subject, a softbox facing the subject, a reflector, and the camera. Power for the flash hitting the back of the subject is set to full. Power for the soft box, lighting the front of the subject is set to 1/8th power. Between the flash on the background and the flash facing the back of the subject, we will get a nice rim light and hair light on our subject.
How much detail you want on your subject's face and front is where you as the photographer, decide what you are trying to achieve, with your image. More power to the softbox gets more detail. Less, gives you closer to a silhouette. No matter what you are trying to accomplish, as with the silhouette, you need to focus on your subject, but expose for your background. This is a setup that will require a few test shots to get exposure just right!
Add Drama: Break The Rules
Both silhouettes and backlighting are a great way to add drama to your photos.
More on Lighting with Flags, Diffusers and Reflectors: http://www.bluefinstudios.com/blog/2013/4/tutorial---reflectors-diffusers-and-flags