Scrap Of Faith

Using Aperture to create Depth of Field


Working out how to control the depth of field in your photos will give you so much creative control over your photos, and is such a huge factor between ‘snapshot’ looking photographs and professional looking photographs.

Depth Of Field is the amount of your shot that will be in focus. A photo with shallow depth of field has a lot of blur, with just a little bit in focus. A photo with a large depth of field has almost all of the photo in focus. Having most of the photo in focus is great for shots like landscapes, where you want to see the foreground, but you also want to see mountains in the distance. But for portraits shallow depth of field tends to be better.

The depth of field you can create, depends on the lens you are using and how wide it will open up. The wider it will open, the more blur you’ll be able to create. Take a look at your lens, and you’ll notice some numbers around the edge of it. They’ll look like 3.5-5.6 if your lens zooms. This means the widest aperture you can get with the lens is f3.5 which will be without zooming in. When you do zoom in, your lens will close up a little and the widest you’ll be able to get will be f5.6.

Here are a couple of pics I’ve taken at the widest and narrowest apertures of my 50mm lens. The first pic is taken at f22. See how everything is in focus, from the carpet (and crumbs!) in the foreground, to the wall in the background.




The next photo was taken at f1.8. Only the point I chose, the first green car, is in focus. The rest is blurred. Your eye is automatically drawn to the part that is in focus.




To do this yourself you’ll need to put your camera into Aperture priority. In this setting you can control what aperture you want to use, and the camera will automatically give you the right shutter speed for the correct exposure. Check your manual if you’re not sure how to do this, but it’s generally a dial on top with an A or Av on it. When you turn the dial (check your manual for your camera again, but it’s generally a wheel near the shutter release button) you’ll notice the ‘f’ number on your LCD panel change. Set it to f22 or as high as you can go, and take a pic. You’ll see everything is in focus like my first pic. Then change it back to F3.5 or as low as you can go. You’ll notice when you are in Av mode, that you get a little focus point in your viewfinder. It will look like a little square. There may be a few of them, but only one will be bold. Line up that point with the part of your scene you want to be in focus and take another pic. Your photo should look more blurry, with the sharper area where you selected it.

Being able to choose which parts of the scene you want to be sharp and in focus will give you so much creative control. By changing only the point you chose to focus on, you change what you are saying is the most important part of the scene, and what you want the eye to be drawn to. Here are a few more examples.


Just a slight move of the focal point for two different perspectives. You can use shallow depth of field to tell a story, or set a scene.While I had a lots of pics of the bride and groom here, this shot was all about the little flower girl who wandered out in the middle of the ceremony. Using a shallow depth of field made the bride and groom blur into the background, ensureing the flowergirls was the main focus of the photo. If everyone was in focus here, it would be a really busy photo, with little impact.

Shallow depth of field lets you focus on the small details... like baby toes :)




Give it a try, and leave a comment with a link to your piccies. You can upload them to the SoF gallery, your blog, photobucket, Flickr etc. Have fun :)