This is the exposure compensation button on a Nikon camera. Different camera companies put it in different places, or embedded in menus, but they all work the same way: letting us fine tune the brightness values of our images. (Don’t mistake this for a similar-looking control near the viewfinder, which is the diopter setting.)
This is an image displayed on the monitor of a modern digital camera. The top frame is set to -1.7 exposure compensation, the middle to 0.0, and the bottom is set to +1.7 exposure compensation.
The fundamental look of our images is controlled by many factors: subject, composition, lighting, focal length, color. One element of our imaging that stands out as particularly important is exposure. Our images are made of light, so how much or how little light we show in them is at their heart.
I thought of this for two reasons. First, someone emailed me with an exposure question. Second, I happened across yet another raging debate on Photo.net this morning about “expose to the right,” a hot-button issue regarding exposure in the digital age.
Before we dive into exposure control, let me stridently assert this: exposure, like most factors in photography, is subjective. If anyone every tells you that your opinion about exposure is wrong, they’re wrong. We all have a unique perspective on imaging.
The email I received, however, was a fairly straightforward question from someone just learning about photography: “I think I have sufficient lighting but my pictures come out dark. Any suggestions?”
The answer is, thankfully, a reasonably easy one: learn how to use exposure compensation. Exposure compensation is the way we tell the camera to expose the sensor to more or less light. On many cameras, it is controlled by a button with a +/- on it. We push and hold the button and turn a dial (the main command dial on Nikons) left or right to change the amount of exposure compensation, usually by one third of an f/stop at a time. When you bought your camera, this value was set to 0.0. We can change it to values like +0.7 or -2.3, and so on. Plus makes the image brighter, while minus makes it darker.
Of note is that exposure compensation is usually disabled in “green box” auto mode or scene modes, so to use it, you need to be in one of three exposure modes, P=Program, A=Aperture Priority, or S=Shutter Priority (Canon cameras use Av and Tv for the last two). (See The PASM for more on these modes.) Also, note that exposure compensation has no effect in manual mode, because in manual mode, we pick all the settings.
I intentionally shot this image of a law ornament at “minus 2.3″ exposure compensation to illustrate a genuinely underexposed image.
This image of the same lawn ornament as above, was made at about +0.3, and looks about right.
I mentioned “expose to the right” earlier, so I should explain: there are those who believe, often very dogmatically, that the histogram (see the image of the display on the back of my camera; the histogram is that thing that looks like little mountain ranges) should be stacked to the right. “Expose to the right” is a worthless tome because it’s only effective some of the time, and treats us as robots who need rules to follow.
In my occupation, news, magazine and sports photography, human faces take priority over other shadows and highlights, so much of the time I try to expose so we can see who, not what.
Exposure can make or break certain images, like this wheatgrass at sunset down by our pond this evening. The camera sees the brightness of the sun in the image and might tend to underexpose it, but vigilant use of exposure compensation results in beautiful moments like these.