Depth of Field is the region of sharp focus in a photograph. It is controlled by three different things:

Aperture

Lens focal length

Distance to subject

The depth of field increases as you stop down the aperture. Each time you double the F-stop (F8.0 to F16.0) you double the depth of field.

The focal length of your lens is also an important part in depth of field. Depth of field increases as the focal length decreases (105mm versus 24mm) with the 24mm lens offering greater depth of field than the 105mm due to image magnification. As you change the focal length by half, you quadruple the depth of field from the same perspective.

Subject distance is the distance your camera is from your subject. The closer the camera is to the subject, the more limited your depth of field. Doubling the camera to subject distance quadruples the depth of field.

Example: if the depth of field is 5 feet at a camera distance of 12 feet, it will be 20 feet (5 x 4=20) if you increase the camera to subject distance to 24 feet (move away from the subject).

You can also change the focal length of the lens by half and this action will quadruple the depth of field, thus maintaining perspective (from 70mm to 35mm).

As I have stated, depth of field can be achieved by using a variety of methods, it is your choice as to which you use. In some situations the choices may be very limited, but, they would surely be limited if you did not know you had any at all.

Aperture settings and depth of field

Lens speed is determined by the largest aperture opening for the lens. High quality fast lenses F1.8, 2.0, 2.8, all have large openings for light to pass through and require more glass, therefor cost more in weight as well as money. What lens you choose to use is strictly up to you. Wide open refers to the maximum opening for your lens, (smallest F stop number-- F2.0 vs.. F22.0, the largest, for example). Depth of field increases as the lens is closed down (going to the larger numbers, F16.0, F22.0)

Focal length and depth of field

Shorter focal length lenses provide high depth of field when using the same perspective. The longer the lens, more limits are being placed on the amount of depth of field available due to image magnification.

Distance to subject and depth of field

The closer you get to your subject, the less depth of field you will be able to achieve. As you move away from the subject, depth of field is increased rapidly.

Field photo tip from the nature photography workshops.

When you have a distant subject, with no close foreground like a scenic landscape with mountain range as an example, you do not need to close down the aperture to F16.0 or F22.0 to get good depth of field. What you would be doing is wasting the opportunity to have a faster shutter speed and crisper or sharper image.

Remember, distance is part of the equation and the aperture will have no effect on the creative depth of field but only plays it's part in proper exposure.

I will use F5.6-F8.0 in this example. This will give me or you 3 stops to add to the shutter speed say from 1/4 sec. where you have a source of movement with the camera to 1/30 sec. which is much more stable- (always use a tripod) trust me, this is a major difference for professional nature photography portfolio images.

We will discuss close-up nature photography from the California nature photo workshops and the role depth of field plays in making a close up macro nature image better.

Photo tip collection for nature photographers learning the basics of creative nature photography California Pictures Nature Photography