Suppose you are walking through Canatara Park and suddenly you spot a beautiful warbler on a branch overhead. It’s the middle of the day with a bright, sunny sky. You excitedly snap several photos, but later when you look at the photos on a computer you are disappointed to see that the bird in the photo is darker than you anticipated.
The problem is that the bird was backlit and this situation is quite common, seeing as birds are often overhead and so is the sun. Even with binoculars, a bird against a bright sky often looks like a silhouette of a bird. Your camera’s sensor that controls exposure has the same problem, it “sees” a small bird and a bright sunny sky and interprets that as “hey, there is plenty of light here so I don’t need to let as much light into the camera to get a properly exposed image”, so it limits the amount of light (typically by reducing shutter speed or decreasing the aperture) thereby giving you the underexposed bird in your photo. (more…)