When it comes to learning basic photography concepts, depth of field (DOF) is one of the most important for beginner photographers looking to make the jump to "intermediate." Understanding what depth of field is, how to alter it in your photographs, and some of the different artistic things you can do with it will all help you progress your photography to the next level.

What Is Depth of Field?

Put simply, depth of field is the distance from your lens at which objects appear acceptably sharp, and this measurement determines which items in your photograph will be in focus and which will be blurry. Here's a great example:

depth-of-field-film-canister

In this photo, the tips of the fingers and the film canister are in focus, and the rest is out of focus. This is a "shallow" DOF, in which only a small portion of the space in front of the lens is acceptably sharp. You can see the difference between a shallow depth of field and a deeper one in these two photos:

flowers-dof-comparison

The same picture was taken at two different apertures (we'll get to why that's important in a moment), and you can see the dramatic difference above. The results are very distinct, and should give you an idea of how you can create different effects in your photography.

Aperture and Depth of Field

If you've read up on your basics of photography, you'll know that aperture is how wide open your shutter is when you take a photo -- this determines how much light hits the sensor of your camera, and also has a big effect on the depth of field. This diagram shows why a larger aperture creates a smaller depth of field:

dof-illustration

If you want to read up on the physics of why it works this way, I recommend checking out the Wikipedia article on depth of field. It has all of the information you could ever want, and a whole lot more. For now, though, suffice it to say that a larger aperture lets in more light and creates a shallower depth of field than a smaller aperture (though both will result in similarly crisp images of the object that you've focused on).

Remember that a smaller f-number is a larger aperture, and vice versa.

The Best Way to Learn: Play Around

You can look at all the diagrams and professional photos you want, but the best way to learn about how to change the depth of field in your photos and how it affects their artistic qualities is to grab your camera and start playing around with different apertures.

The best way to do this is in aperture priority mode, which will allow you to change the aperture of your lens without having to worry about shutter speed, which will be adjusted automatically based on your choice.

aperture-priority-mode

Now, here are five small experiments you can do to get used to working with depth of field. I've taken a few photos to show you what I mean, but use your imagination in trying these things out!

Lesson #1: Close vs. Far Focus

When you're first learning to use DOF to your advantage, it can seem like a shallow depth of field will always be closer to your camera. This exercise will show you that it doesn't work that way. Grab your camera and find a place where you have a good shot of two different objects, one that's a bit further away than the other.

dof-practice-shallow

Focus on the close object and take a photo, then focus on the far object and take another one.

dof-practice-far

You've now completed your first experiment with depth of field! It's not very exciting, but if you can do this, you can do pretty much anything related to DOF.

Lesson #2: Creating a Transition

One of my personal favorite things to do with a shallow depth of field is to create a transition along an object, so that the closest portion is in focus and there's a transition going down the length of the object as it gets less and less in focus. Here you can see what I mean:

dof-practice-transition

The shot above follows the edge of my desk, and you can clearly see the transition from in-focus to out-of-focus. This is a cool way to create depth in your photos, and it can also serve to draw the attention to a specific part of the image.

Lesson #3: Isolating Your Subject

Most of the times that you see shallow depth of field used, you'll see it used to isolate a subject -- the subject will be in focus, while the background will be blurry.

dof-practice-isolation

In the image above, I've isolated the foreground book from the stacks of books in the background. This is a great skill to learn for any kind of photography, from outdoors and nature to shooting portraits!

Lesson #4: In-Focus Background

This might be an exercise more in using your photographic eye than in depth-of-field technique, but it's a really good one nonetheless. Sometimes the background of a particular image can be the focal point of a photo, and whatever's in the foreground will better serve out-of-focus.

dof-practice-background

As you can see, this can be used to artistic effect to draw attention to a specific part of the photo while still giving another part of the image a sort of "secondary" focus.

Lesson #5: Mid-Range Focus

Until now, either the foreground or the background has been in-focus. In this final task, you'll want the foremost part of the foreground as well as the background to be out of focus, and something in the middle in focus.

dof-practice-mid

You may or may not find this a very useful thing to practice, but it's a good way to deepen your skills with shallow depth of field photography.

Get Out and Practice!

Whether you're just learning about adjusting the depth of field in your photography or you've been doing it for a while, the best way you can hone your skills is to practice and be honest with yourself about how your shots came out. Use large and small apertures to adjust the depth of field in your images, and get creative!

Do you like to shoot shallow-depth-of-field photos? Or do you tend to get everything in the frame in focus? What other activities have helped you develop your skills? Share your thoughts and tips below!

Image credits: Ben Seidelman via Flickr, Fir0002/Flagstaffotos via Wikimedia Commons (2), Chabacano via Wikimedia Commons.