How To Take Charge Of Depth of Field In Your Photography

Understanding how to control depth of field in your photographs is one way to take creative control of your images.

When an image has a large depth field it means that everything from the foreground to the background is in focus.

A shallow depth of field is when only a portion of the image is in focus. This can mean anything from the background being slightly soft to only a razor thin slice of the image being sharp.

As an artist you don’t always want your images to appear exactly as your eye saw the scene. You want to draw the viewer’s eye to something in particular, to emphasize one thing over another in an image.

So, how do you do that? I’ll show you …

Depth of field is controlled by three things:

1. Aperture

Aperture is the size of the opening through which light travels to your camera’s sensor and it is expressed in f-stops.

The smaller the f-stop number the larger the opening. That’s kind of confusing isn’t it? It’s because the f-stop number is actually a ratio. But I don’t want to get into too much mathematics here, just remember it’s like a fraction and 1/2 is bigger than 1/8 so f/2 is bigger than f/8.

aperture

The larger the opening the more shallow the depth of field. In other words the amount of your scene that will be sharp, measuring from the object you focussed on, is smaller.

These two images illustrate the effect of aperture on depth of field. (Please click on the images to view larger versions.)

Victoria Legislature Totem
35mm at f/20: Everything is in focus

Big Balls at Seattle Center
35mm at f/4.5: Only the ball in the foreground is in focus the rest of the image is soft

2. Your lens

Just to make it even more complicated, all this changes with every lens you have!

So the setting of f/4 ,for example, is actually different depending on the focal length of your lens. f/4 on a telephoto lens like a 200mm is actually a larger opening than f/4 on a 50mm lens.

That means when you use your telephoto the depth of field is smaller than the same setting on a mid-range lens. (Remember large opening means shallower depth of field.) Conversely f/4 on a wide angle lens has a much bigger depth of field than a mid-range lens.

Cherry Blossoms
250mm at f/5.6

With the telephoto lens at f/5.6 the depth of field is extremely shallow with only the blossoms in the immediate foreground in focus. I bet you didn’t know there is an ugly blue house behind those flowers! Making use of depth of field is how I made the house invisible.

New Orleans Street Busker
20mm at f/5.6

With a wide angle lens at f/5.6 the depth of field is pretty big. In this case the building behind the musician is totally in focus. It probably would have been a better image if I had used a telephoto lens and moved farther away, but that was not physically possible unfortunately.

3. The distance between you and the subject

Remember the area of the scene that is sharp is measured from the subject you are focussed on. So if you are making an image of a cityscape and the whole city is miles away, you can get away with a larger aperture opening and everything will still be sharp because the whole subject is in the distance.

On the other hand if you focus on something that is a few meters away and part of your scene is miles away then you will need a small aperture if you want everything to be sharp.

A few more examples to demonstrate depth of field:

Convict Lake, California
16mm f/22: Everything is in focus
Spring Tulips
70mm f/4.0: Subject in focus, background totally out of focus
Hatley Castle Japanese Garden, Victoria, BC
85mm f/11: Subject in focus, background soft but still recognizable
Fly and Daisy
250mm f/5.6: Razor thin area only is in focus

When you are photographing be conscious of how you want the background in your image to look and take control of the depth of field!

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Comments

    • says

      Hi John, I know I think depth of field is one of the hardest concepts to learn. And, you are right, there seems to be many ways of explaining it many of which contradict each other. Thank you very much for your comments, I appreciate it.

    • says

      Hi Michael, I think it depends on the camera. When I used to use a compact camera in auto mode, my camera always chose a large aperture with small depth of field. I don’t know how the cameras choose these settings. But that is one of the best reasons to get out of auto mode and start taking control of what you want the image to turn out like instead of letting the camera make the decisions. Try using aperture priority and see what your camera does then. Thank you very much for contributing your comments, they are always welcome!

  1. Berta says

    Anne, all the depth of field tutorials that I have read before only cover the lens aperture part, but they seem to neglect the fact that the same aperture gives you different depth of field depending on the focal length, I did learn that by experience. And for me it is very important, that has been the reason that have made favour some lenses over others over time. Thanks for putting it all together in such clear way!

    • says

      Thank you for your great comments Berta. I too have discovered this with experience and often choose one lens over another just to get the depth of field and perspective I want. I’m glad you enjoyed the post.

  2. SATISH says

    ANNE, I AM A NOVICE COMING OUT OF THE AUTO INTO MANUAL MODE. I HAVE BEEN TRYING TO GET AN IMAGE WITH A SHALLOW DOF WITH MY NIKON COOLPIX 4500 BUT HAVE NOT SUCCEEDED. WITH A LARGE APERTURE SET IN MANUAL MODE, ONCE I ZOOM IN, THE APERTURE CHANGES AUTOMATICALLY SO THAT I DON’T GET A BOKEH. IF I DON’T ZOOM IN THE EXPOSURE HAS TO BE MANAGED. DO I NEED TO USE AN SLR CAMERA IN THIS CASE TO GET THE RESULTS OF A PROPER DOF? AND YOUR EXPLANATION IN YOUR BLOG IS VERY PLEASING, SIMPLE & DETAILED TO SAY THE LEAST.

    • says

      Hi Satish, sorry for the delay in my reply. If your camera has an aperture priority mode, that’s where you want to be. Then you can set the aperture for the largest it can be (say 2.8) and the camera will then calculate the appropriate shutter speed. I just looked up your camera and it does have aperture priority. You hold down the “mode” button while turning the command dial until the mode “A” displays in the lower left corner of the LCD. Then, once it is in aperture mode, you use the command dial to select the aperture. I hope that helps!

      By the way, I found that information in the user guide here:
      http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/4500/index.html

  3. Luffy says

    Thank you very much, Anne.

    I’m still a beginner and your topic is the best that i’ve ever read! No need for blah blah blah, just direct to the point :)

  4. Sherry Hogue says

    Thank you Anne for your excellent article and beautiful photos on DOF.
    I shoot with a crop sensor camera and wonder when choosing a lens for a particular DOF do I need to take into consideration the crop factor of my camera? I am assuming your photos were shot with a full frame camera.
    Thank you Anne for sharing your knowledge and wonderful adventures with your photography. You are most encouraging to this beginner.

Trackbacks

  1. [...] How To Take Charge Of Depth of Field In Your Photography – quite simply one of the best articles I’ve ever read that takes the reader through the technicalities behind controlling depth of focus.  This powerful tool in the photographer’s arsenal is the result of a complex set of relationships that envelope focal length, distance to subject and aperture size, and Anne McKinnell delivers a very easy to digest article that removes the mystery behind it all. [...]

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