Depth Of Field

Depth of field (DOF)is a function of focal length, distance to subject and a property of optics. Find out how you can use depth of field creatively to enhance your photos.

DOF is a measure of how much of the subject, from near to far in the photo, appears to be in focus.

It is a function of the lens aperture, focal length and distance to the subject.

The way to adjust your DOF on your digital SLR camera is to adjust your aperture. You can either set your camera to “Aperture Priority” mode or “Manual” mode.

In the flower photo below, the petals in front and the back are blurred.

In general…

  • The smaller the aperture, the deeper the DOF.
  • The shorter the focal length, the deeper the DOF.
  • The farther your subject, the deeper the DOF.

I consider DOF control to be key to mastering photography basics.

Depth of Field Basics

If you are used to a point-and-shoot digital camera, DOF was probably not a concern to you.

Most of these cameras had short focal lengths and rendered pictures sharp from a few feet to infinity. Sometimes this is a good thing but it can be difficult for closeup photography.

depth of field

In general, the larger the f-stop number, the more of the photo that appears to be in focus.

The f-stop number corresponds to the aperture. The larger the f-stop number, the smaller the aperture.

So how do you, as a digital SLR photographer, make use of this information?

For landscape photography and closeup photography, you will want to maximise your DOF to get as much of the picture in focus.

Portrait photography is a little different. If the intention behind your photo is to isolate the subject, you will want a shallow DOF. If you are photographing a group of people, you will want a deeper DOF to get everybody in focus.

Depth of Field Preview Button

Most digital SLR cameras have a DOF preview button. This button is located on the camera body near the lens mounting ring.

By depressing the DOF preview button, the lens will stop down to the selected aperture. There are two consequences to this:

  • The viewfinder may become darker if you use a small aperture due to less light coming in through the lens
  • The rest of the scene becomes sharper

The DOF preview button is very handy.

Once you get past “it’s too dark” stage, you will be able to make better and more critical judgements on the kinds of photos you wish to take.

Love your camera. Love yourself. Love your photos.