Depth of Field & Aperture Explained

You may never have thought that the aperture or the diameter of the Iris in your camera is not only for controlling the amount of light that passes through to your sensor or film, but how you control your Depth of Field (D.O.F) in your photos.

Smaller Aperture = Larger D.O.F

The Iris diaphragm in your camera looks like this:

Large Aperture f/3.5

Small Aperture f/22

In the image below there is a subject in the foreground and some scenery in the background, also in focus. Both the subject and scenery are in perfect focus, because the D.O.F is higher due to the smaller aperture. This technique is great for getting everything in one shot like for family photos.

Depth of Field High/Aperture Small

In the image below there is a subject in perfect focus in the foreground and some blurred/Out-of-Focus scenery. This image has a lower/shallower D.O.F due to the larger aperture, however this is a good technique to really make the subject the main focal point and jump out a little.

Depth of Field Low/Aperture Large

So, for your future photo shoot remember that, whether your wanting to get all your surroundings in (subject + scenery): Smaller Aperture

Smaller Aperture = Larger D.O.F

Or, you’d like your subject to really pop out and be the main focal point: Larger Aperture

Aperture large = Shallower D.O.F

Along with the Depth of Field (D.O.F) is the Focal-Point which must not be confused with D.O.F.

In this photograph we see a chain clearly in focus on the few chain-links in the foreground:

Focal-Point Foreground f/10

Then in the next photograph we can see the focus is now on the few chain-links in the background:

Focal-Point Background f/10

The D.O.F has not changed (as the EXIF data proves), but the Focal-Point has, because I manual focused my lens to those different areas on the chain.

Although, DOF is a function of f/stop and magnification – magnification changes with focus distance. (thanks to Chris for the explanation)

Here are some examples of why the D.O.F can help bring out your subject from the clutter in the background:

1. In this first image we can see that the clutter of the background can e very distracting to the subject because our eyes are able to see the background clearly.
   

   Larger D.O.F f/22

2. Whereas this second, with the blurred background helps our eyes focus on the subject.
   

   Shallower D.O.F f/5.6

Please comment below if you have any questions and I’ll answer them ASAP!

All images on this site are copyrighted – All Rights Reserved.

Written by Mike

Deprecated: Function the_author_description is deprecated since version 2.8.0! Use the_author_meta('description') instead. in /home/scottp12/public_html/wp-includes/functions.php on line 5453
Michael Scott is the publisher and photographer behind Scott Photographics! He is very passionate about his photography and enjoys sharing the best of his experiences for others to enjoy too! Contact Mike via email!