There are three ways that your subject’s contrast range can stack up against your camera’s ability to capture it: the subject’s contrast range can be smaller than, equal to, or greater than the capacity of your sensor. Each situation requires specific and targeted action:
As long as the contrast of the subject is not larger than the dynamic range of your sensor—which is usually about nine stops—you can capture all the image information. If you don’t expose your image incorrectly (a), you can target your exposure either on the highlights (b) or the shadows (c). Many times, however, you will encounter a subject whose contrast exceeds the dynamic range of your camera. In these cases at least some of the image information will be lost in the highlights or shadows (d). Your job is to determine the sacrifices that are least harmful to your overall image.
You can use spot metering to measure the contrast range of an image. Meter the brightest and darkest points in your image and calculate the difference between the aperture/shutter speed combinations in whole stops. This process is somewhat laborious, but it can be helpful with studio photography and architecture or landscape images. You can produce digital negatives that contain a maximum amount of image information, which can be used to produce high-quality, fine-art images