Nikon D7000 Motion and Depth of Field


There are distinct characteristics that are related to changes in aperture and shutter speed. Shutter speed controls the length of time the light has to strike the sensor; consequently, it also controls the blurriness (or lack of blurriness) of the image. The less time light has to hit the sensor, the less time your subjects have to move around and become blurry. This lets you control things like freezing the motion of a fastmoving subject or intentionally blurring subjects to give the feel of energy and motion (Figure 2.11).

A slower shutter will convey motion when photographing moving vehicles. How much motion you want to show will depend on the shutter speed used. Here I wanted the image of the taxi to be very blurred, so I used a very slow shutter speed. If I had wanted the taxi to be less blurry I would have used a faster shutter speed.

The aperture controls the amount of light that comes through the lens, but also determines what areas of the image will be in focus. This is referred to as depth of field, and it is an extremely valuable creative tool. The smaller the opening (the larger the number, such as f/22), the greater the sharpness of objects from near to far. A large opening (or small number, like f/2.8) means more blurring of objects that are not at the same distance as the subject you are focusing on (Figure 2.12).

Isolating a subject is accomplished by using a large aperture, which produces a narrow area of sharp focus. Here I was able to isolate Tensing’s pads by using the largest available aperture.

As we further explore the features of the camera, we will learn not only how to use the elements of exposure to capture properly exposed photographs, but also how we can make adjustments to emphasize our subject. It is the manipulation of these elements—motion and focus—that will take your images to the next level.