Chriscrawfordphoto
Real Men Shoot Film.
Scenes that are backlit, or strongly side-lit, are very difficult to expose correctly. The high contrast light means that the brightest and darkest parts of the scene might fall outside the dynamic range of your digital camera.
A Reflected Light Meter, like that built in to your camera, will underexpose the scene. The bright light from behind the subject will fool the meter, causing the backlit subject to render very dark, possibly so dark that little or no detail is visible.
An Incident Light Meter is usually the best type of meter for digital work because it ignores the subject and just measures the light that hits the subject. Normally, an incident meter cannot be fooled by very bright or very dark subject matter, as a reflected light meter can.
Backlit and strongly sidelit scenes are an exception. The incident meter is used by standing at the subject position and pointing the meter's white dome back toward the camera lens. The hemispherical dome simulates the three-dimensionality of an average subject; and it can take into account light from straight on, as well as side-lighting, if the lighting angle is not too severe. In a backlit scene, the whole dome is in shade and does not see the light coming from behind. The result is an overexposed photograph.
Solutions
One solution is to use a handheld spotmeter and carefully measure the brightness difference between the darkest and lightest parts of the scene that you want to retain detail in, using those readings to calculate exposure settings that will leave all or most of the scene's brightness range within the dynamic range of your camera's sensor.
This works wonderfully, but is cumbersome and is difficult for beginners as it requires some testing to determine your camera's dynamic range, and experience in knowing what areas to measure in the scene. If you're interested in learning to use a spotmeter, see my Spotmetering Tutorial.
An Easier Way: Incident-Reflected Average
A simpler solution is to take two readings with a handheld meter, a reflected light reading and an incident light reading. Then, you average them!
This technique is fast and easy to learn, and works well for most backlit and sidelit scenes. If the brightness range in the scene is very wide, you may have to use the shadow and highlight recovery sliders in your RAW processing software (like Lightroom or Capture One). This technique works best if you shoot RAW, rather than JPEGs.
This technique was invented in the 1960s by Jack Dunn, a British engineer who did pioneering research into exposure metering in the mid 20th Century. Dunn wrote, with George Wakefield, a book called "Exposure Manual." If you're as big of a meter geek as I am, you want to get hold of this book.
I also have a tutorial video on YouTube showing how I edited a photograph that I made using this exposure technique.
Example #1
Exposure determined with a reflected light meter.
Exposure determined with an incident light meter.
Exposure determined by averaging an incident light reading and a reflected light reading.
The final image after adjusting the shadow and highlight recovery sliders in Lightroom.
As you can see in the finished image above, this technique produced a beautiful rendering that has good detail in the highlights and shadows, despite the very high brightness range in the scene.
It was very simple to do in the field, taking about 30 seconds to make the two readings and average them.
Modern cameras have "Evaluative" metering systems (also known as Matrix Metering) that analyze the scene to compensate automatically for such difficult lighting situations. In my experience, they sometimes work well and often do not.
The incident-reflected average technique has been far more accurate for me.
A Reflected Light Meter, like that built in to your camera, will underexpose the scene. The bright light from behind the subject will fool the meter, causing the backlit subject to render very dark, possibly so dark that little or no detail is visible.
An Incident Light Meter is usually the best type of meter for digital work because it ignores the subject and just measures the light that hits the subject. Normally, an incident meter cannot be fooled by very bright or very dark subject matter, as a reflected light meter can.
Backlit and strongly sidelit scenes are an exception. The incident meter is used by standing at the subject position and pointing the meter's white dome back toward the camera lens. The hemispherical dome simulates the three-dimensionality of an average subject; and it can take into account light from straight on, as well as side-lighting, if the lighting angle is not too severe. In a backlit scene, the whole dome is in shade and does not see the light coming from behind. The result is an overexposed photograph.
Solutions
One solution is to use a handheld spotmeter and carefully measure the brightness difference between the darkest and lightest parts of the scene that you want to retain detail in, using those readings to calculate exposure settings that will leave all or most of the scene's brightness range within the dynamic range of your camera's sensor.
This works wonderfully, but is cumbersome and is difficult for beginners as it requires some testing to determine your camera's dynamic range, and experience in knowing what areas to measure in the scene. If you're interested in learning to use a spotmeter, see my Spotmetering Tutorial.
An Easier Way: Incident-Reflected Average
A simpler solution is to take two readings with a handheld meter, a reflected light reading and an incident light reading. Then, you average them!
This technique is fast and easy to learn, and works well for most backlit and sidelit scenes. If the brightness range in the scene is very wide, you may have to use the shadow and highlight recovery sliders in your RAW processing software (like Lightroom or Capture One). This technique works best if you shoot RAW, rather than JPEGs.
This technique was invented in the 1960s by Jack Dunn, a British engineer who did pioneering research into exposure metering in the mid 20th Century. Dunn wrote, with George Wakefield, a book called "Exposure Manual." If you're as big of a meter geek as I am, you want to get hold of this book.
I also have a tutorial video on YouTube showing how I edited a photograph that I made using this exposure technique.
Example #1
Exposure determined with a reflected light meter.
Exposure determined with an incident light meter.
Exposure determined by averaging an incident light reading and a reflected light reading.
The final image after adjusting the shadow and highlight recovery sliders in Lightroom.
As you can see in the finished image above, this technique produced a beautiful rendering that has good detail in the highlights and shadows, despite the very high brightness range in the scene.
It was very simple to do in the field, taking about 30 seconds to make the two readings and average them.
Modern cameras have "Evaluative" metering systems (also known as Matrix Metering) that analyze the scene to compensate automatically for such difficult lighting situations. In my experience, they sometimes work well and often do not.
The incident-reflected average technique has been far more accurate for me.
