Making Black Tones, Black
Tell me, what’s wrong with this picture?
But what if I presented this image as it should have been shot with proper metering?
The difference is the first image is okay, but black is not black. This is because your camera is set to believe the world in front of it is not black or white, but neutral gray. Goofy, you might say, but it is true.
The effect this has on photos is, when the area in front of the metering spots (see this post for a refresher on where your camera’s metering spots are) is predominantly black or dark, your camera is set to assume there is something neutral gray there instead. It then tries to match the metering to neutral gray, making black items not so black. They move toward neutral gray.
What do you do to fix this?
Here’s the experiment you can run:
1) Set you camera on a table and switch it to Aperture Priority mode.
2) Set your ISO to 400 and place a black object in front of your camera, about four feet away. Make sure the black object takes up the central area of the field of view, as in the image above. It can fill the whole screen if you like.
3) Take a photo.
Take a look at your photo and I’m willing to bet it is like the first image. The black object is not really black, but moving toward neutral gray. Now then…
4) Change the Exposure Bias/Exposure Compensation of your camera to -1.3. This is one and one third stops under-exposed.
5) Take another photo.
Can you see the difference in the two images? Take a look at the histogram for each.
The one that is better exposed (hint: the second one) should be pushed more to the left side while the first one is trying to be more evenly spread. You don’t want even, you want black to be black!
When To Use This Technique
You will use this technique any time there is a large black or dark area that takes up most of the metering spots of your camera. Otherwise, your camera will make an incorrect exposure.
This problem can be eliminated completely by shooting in Manual Mode, at which point your camera will complain you are about to mess up. At that point, you ignore it and shoot any way.
The important part to remember is your camera’s meter is a tool for figuring out which ISO, Aperture and Shutter Speed to use. It is not perfect and makes an assumption about the world in front of the camera. When that world does not meet your camera’s assumption, you need to make adjustments. Or shoot in Manual Mode.
Questions? Pop ’em like Pez in the comments section below. or email me at email@example.com.
Photography Basics – A 43 Day Adventure, and its companion 40 Photography Experiments, are series written by professional photographer Peter West Carey. The series are designed to unravel the mysteries of photography, helping you can take better pictures. Subscribe here to receive all the updates and bonus material. Your comments are always welcome.
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