Exposure

Exposure is how much light reaches the sensor. Our goal is a proper exposure. Just the right amount of light. It’s the Goldilocks scenario. Too much light and our photos are overexposed. They will be too bright. Information is lost if areas are overexposed to the point of becoming a pure white and that information cannot be recovered.

Too little light and we end up with underexposed images. The photos will be too dark and some areas will be pure black, again missing information that cannot be recovered.

So our goal is a proper exposure. In general this means a wide range of tone, ranging from dark areas to bright but retaining detail throughout all or most of the image. There are exceptions of course. In a photo of a snowman against white snow, proper exposure would not include a wide range. Most or all of the image would be bright. But our goal would still be to maintain detail and information in those bright areas.

Notice the pure white highlights in the first photo. The detail is lost and couldn’t be recovered in Photoshop. The same is true of the dark areas in the third image. Only the middle image has a full range of tones and is properly exposed. This middle image has a lot of information that could be further adjusted in Photoshop.

We control exposure with three tools, called the Exposure Triangle.

• Shutter Speed
• Aperture
• ISO

Together these three tools form what we call the exposure triangle as outlined in the text and in this week’s video tutorial. This is probably the hardest technical skill to internalize. By that I mean, it takes many students a while to be able to quickly set a proper exposure. So don’t become frustrated if you don’t get it at first. But don’t expect to get it without practice and repetition.