Specular highlights: How to exposure correctly for scenes that contain brilliant reflected highlights.
Specular Highlights
Specular Highlights
Taking
accurate light readings is very important in getting good exposures,
whether you're metering in a manual mode or your automatic meter is
doing the work for you. Metering scenes of average brightness, where
nothing is radically darker or brighter than the majority of tones in
the scene, is fairly simple and most built-in meters do a very good job.
Problems
arise when there is excessive contrast in a scene, because the dynamic
range (the dark-to-light contrast range) extends beyond the camera's
ability to record those tones. One type of contrast situation that all
cameras have a tough time with is what's called a specular highlight.
These are extremely bright spots in a scene, created by a direct
reflection of the sun or some other light source (like flash reflecting
in a mirror), and they cause the meter to grossly underexpose (i.e.
give too little exposure) an image because they make the meter think
that the entire scene is brighter than it is.
There's
really no safe way to meter with a specular highlight other than to
exclude it from your composition during the metering phase. In the shot
here, for example, I wanted the reflection of the sun in the water, but
I knew that if I metered with that spot in the frame, the whole scene
would have been drastically underexposed. Instead, I took a reading
from the boat and the water (which already constituted a fairly
contrasty scene) while carefully excluding the bright spot in the
water. Then I simply locked in that reading by holding the
shutter-release button halfway down and recomposed the scene.
An alternative is to change your angle to the reflecting surface so that the highlight disappears, or to simply high the highlight behind part of the subject. In the case of the shot of the boat's bow, for example, I could have changed my shooting height or angle to hide the highlight behind the boat. Since I liked the look of the highlight, however, I chose to let it remain in the frame, but metered around it. Keep in mind that because the highlight is extremely bright, there won't be any detail in that area--you'll simply get a bright blog of reflected light.
The bottom line: Beware any very bright pockets of light, especially around reflective surfaces, and you'll get much more consistent exposure results.
Specular highlights are very common when shooting water scenes where the sun is bouncing off of the water. Again, the simplest way to exposure correctly is to try and reframe a scene to eliminate the highlights during metering.
Entire Site Contents Copyright 2012 Jeff Wignall
An Ambitious Dogs Production In Association with Boo Boo & Mama Cat Films Please also visit my Photo Tip of the Day blog.
