Nikon D7000 manual Getting a Handle on Exposure

96 David Busch’s Nikon D7000 Guide to Digital SLR Photography

correct exposure is one of the foundations of good photography, along with accurate focus and sharpness, appropriate color balance, freedom from unwanted noise and exces- sive contrast, as well as pleasing composition.

The Nikon D7000 gives you a great deal of control over all of these, although compo- sition is entirely up to you. You must still frame the photograph to create an interest- ing arrangement of subject matter, but all the other parameters are basic functions of the camera. You can let your D7000 set them for you automatically, you can fine-tune how the camera applies its automatic settings, or you can make them yourself, manu- ally. The amount of control you have over exposure, sensitivity (ISO settings), color bal- ance, focus, and image parameters like sharpness and contrast make the D7000 a versatile tool for creating images.

In the next few pages I’m going to give you a grounding in one of those foundations, and explain the basics of exposure, either as an introduction or as a refresher course, depending on your current level of expertise. When you finish this chapter, you’ll under- stand most of what you need to know to take well-exposed photographs creatively in a broad range of situations.

Getting a Handle on Exposure

In the most basic sense, exposure is all about light. Exposure can make or break your photo. Correct exposure brings out the detail in the areas you want to picture, provid- ing the range of tones and colors you need to create the desired image. Poor exposure can cloak important details in shadow, or wash them out in glare-filled featureless expanses of white. However, getting the perfect exposure requires some intelligence— either that built into the camera, or the smarts in your head—because digital sensors can’t capture all the tones we are able to see. If the range of tones in an image is exten- sive, embracing both inky black shadows and bright highlights, we often must settle for an exposure that renders most of those tones—but not all—in a way that best suits the photo we want to produce.

For example, look at two bracketed exposures presented in Figure 4.1. For the image at the left, the highlights (chiefly the clouds at upper left and the top left edge of the sky- scraper) are well-exposed, but everything else in the shot is seriously underexposed. The version at the right, taken an instant later with the tripod-mounted camera, shows detail in the shadow areas of the buildings, but the highlights are completely washed out. The camera’s sensor simply can’t capture detail in both dark areas and bright areas in a sin- gle shot.

The solution, in this particular case, was to resort to a technique called High Dynamic Range (HDR) photography, in which the two exposures from Figure 4.1 were com- bined in an image editor such as Photoshop, or a specialized HDR tool like Photomatix