Depth of field (DOF) is one of the most important factors in determining the look and feel of a photograph. It’s also the most overlooked for photographers moving from a point-and-shoot camera to a digital SLR camera. The dSLR (and most of the ultra-zooms) offers huge amounts of control over depth of field, and you should know how to utilize that control.

Depth of field refers to the distance (depth) from the focus point that a photo will be sharp, while the rest becomes blurry. A large, or wide, depth of field will result in much of the photo in focus. A small, or narrow, depth of field will result in much more of the photo out of focus. Neither approach is better or right, and which depth of field to use is up to you, the photographer. You may have different reasons for choosing a certain depth of field including artistic effects, bringing attention to a subject, or crisp representation of a scene.

There are four main factors that control depth of field: 1) lens aperture, 2) lens focal length, 3) subject distance, and 4) film or sensor size. Your film or sensor is pretty well set, so you won’t have much luck changing that. Your focal length and distance to the subject are usually determined by your choice of composition. So the lens aperture is your primary control over depth of field.

Before I get to the tips, let’s get a few things straight:

  • BIG APERTURE = SMALL F/NUMBER = SMALL DEPTH OF FIELD
  • SMALL APERTURE = BIG F/NUMBER = BIG DEPTH OF FIELD
  1. Aperture Control - Large apertures (small f/numbers) cause a narrow DOF, while small apertures (large f/numbers) cause a wide DOF. To bring attention to a subject by blurring a background, shoot with f/numbers like f/2.8, f/4, or f/5.6 – this is called “selective focus”. To bring the whole scene into focus, shoot with f/numbers like f/16 or f/22.
  2. Avoid Excess DOF - If you want to bring an entire scene into focus and keep it sharp, you’ll use a small aperture. But be careful not to go too small. Lens sharpness will start to deteriorate at the smallest apertures. Use enough to get what you want, and no more. You may have to experiment a bit to get a feel for how your camera and lenses work at different apertures.
  3. Focus Point - The DOF extends behind and in front of the point of focus. It usually extends further behind than in front, though. So keep this in mind when choosing your focus point; you’ll want to focus about 1/3 of the way into the scene rather than 1/2 way.
  4. Use a Tripod - As you stop down the lens for greater depth of field, you’re also letting less light into the camera. To compensate for this and maintain correct exposure, you’ll need to either use longer shutter speeds or a higher ISO. The ISO can only be increased so much before noise artifacts will become an issue, so you’ll most likely want to lengthen your shutter speed. If you’re shutter speed is too long, you’ll need a tripod (or some type of stabilization) to deal with this.
  5. DOF Preview - When looking through the viewfinder of an SLR camera, you’re seeing the world through the lens. You can easily see your resulting composition and point of focus, but the depth of field you’re witnessing is a little false. You’re seeing the resulting depth of field for the largest aperture of the lens, no matter what f/number you’ve chosen. Most newer dSLR cameras have a feature called DOF preview that allows you to stop the lens down to the chosen aperture so you can see the true depth of field. What you’re seeing usually gets darker because you’re letting less light through, but you should still be able to see the scene (unless the aperture is very small and it’s dim out).
  6. Focal Length - As I mentioned, your focal length is usually determined by your choice of composition, but you should know how it affects your depth of field. Longer focal lengths (200mm) have less depth of field than shorter focal lengths (35mm). Just keep this in mind when you’re trying to achieve a certain depth of field — you may need to alter your focal length in addition to your aperture.

So there are your basic tips for controlling your depth of field when taking photographs. The best way to learn how to control DOF is to set your camera to aperture priority mode (if it has it) and go take some pictures. Photograph the same subject many different times while altering the aperture, point of focus, and focal length (if you have multiple lenses or a zoom lens). Either write down your settings you used for each picture or use software to view your camera’s settings while you look through the pictures on your computer. You’ll begin to see how these different things affect your photos.

The photo below shows a slightly out of focus background. I took several shots at various apertures, and I decided that I liked having the building out of focus but I wanted it to keep its main features. So the best settings (in my mind) were at a fairly large aperture with a slightly shorter focal length (opposed to 150 or 200mm). In fact, my focal length was determined by the composition and I probably couldn’t get a much further away due to the angle I was shooting at.

Photo of the Day…

Princeton Cat

Photo by Brian Auer
11/07/06 Princeton, NJ
Shot taken on the Princeton campus
Konica Minolta Maxxum 7D
Konica Minolta AF DT 18-200
80mm equiv * f/5.6 * 1/350s * ISO100

17 responses


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These are really great tips, Brian. And seeing the photo as an example makes them even better. Thank you.
Do you think it’s possible to achieve similar effects with a point-to-shoot cameras?

March 1, 2007 6:51 pm

Ooh, good question. Yes, but how much will depend on the camera.

If the camera has manual controls for aperture, that definitely helps. It also helps if the camera has zoom, as most P&S cameras do. The problem with creating a shallow depth of field comes from the fact that the sensor is so small, and as a result the lens is close to the sensor — thus creating very small focal lengths. My P&S has a focal length range from 6mm to 18mm — which is very small. They create an effective focal length much higher due to the small sensor size. As I said in the tips, a short focal length will produce an image with nearly everything in focus.

So to blur the background using a P&S, you’ll get your best results if you zoom in all the way, focus on something close (you don’t want to focus out to infinity), and have a background that is much further away. So your two points of control are focal length and subject distance. I just gave it a shot with my camera, and it does work.

March 1, 2007 8:27 pm

Thanks for the detailed answer, Brian.
Once it stops raining here, I’ll give it a try.

March 2, 2007 10:17 pm

I can get pretty much same results on my P&S Olympus 770 using zoom and A mode. However the light is important and when it is darker the results are no good.

Thanks for the article. I like that you cover everything briefly and easy to understand for a beginner.

July 6, 2007 4:25 am

Very good article! I can increase my DOF effect with a P&S by using NeatImage in post precessing. It really works but only if like you said, I use the zoom or macro mode. This NeatImage stuff does not create the DOF effect, but it increases it.

July 24, 2007 2:59 pm

i was able to achieve good DOF photos with my point and shoot camera (canon ixus 4)! cf droplets and flowers photos in my flickr stream — http://www.flickr.com/photos/bwillib/

January 14, 2008 12:56 am


Hi Brian I just got into your site by accident and I’m glad because I’m taking photography and the first month I didn’t get it at all. But thanks to you and someone who I know is a photographer I understand it much more. Can please talk about small depth of field more with maybe some images as example like the Princeton image. Also how to get a blurred image to apply it to movement, how to be able to apply the rule of thirds. PLease I just don’t get my professor I would appreciate it. Good job with the website, the writing is very comprehensible for photography.
Thanks, Melinda

March 20, 2008 3:59 pm

Well I’m glad you found my blog!

I’d love to cover the topics you’re asking about, but I think I’ll direct you to my friend for the moment. Neil Creek is writing a massive series at the digital Photography School right now. He’s covering the very basic subjects at the roots of photography in a way that I’ve never seen before. So far he’s covered the nature of light, lenses and focus, and an introduction.

At some point in his series, he’ll probably be digging into depth of field, f-numbers, and camera controls.

March 20, 2008 7:31 pm

Hi

Very interesting and informative article. I’m looking at buying something like a Nikon D60, but, being new to DSLRs, the f-stops offered seem very narrow on something like the 18-55mm f/3.5-5.6G DX VR Lens. To me, 3.5 to 5.8 hardly feels like a choice at all. Am I missing something?

Thanks
Ethan

April 15, 2008 8:29 am

Ethan, good question — I’m sure you’re not the only person to be asking the same when looking into dSLRs. The f-number designations on a lens is only an indication of the lowest f-numbers (or largest apertures). Most zoom lenses will have a range of f-numbers, which (in your example) indicates that the lens is capable of f/3.5 (and up) at 18mm and f/5.6 (and up) at 55mm. The max apertures of such lenses are typically somewhere in the range of f/11 to f/44 — but you’ll have to read up on the detailed specs for a particular lens to find out what that number is. Make sense? Let me know if you need more clarification.

April 15, 2008 10:38 am

Thank you very much, Brian. That makes much more sense. There is one more thing that you could perhaps clarify. Camera companies seem to spend so much space in their blurbs telling us all about the fantastic new developments at the expense of omitting useful information about manual settings. I’ve noticed that these cameras do not have an f-stop ring. In your experience, if a camera advertises itself as having fully manual capability, will there be an ‘electronic’ or virtual f-stop ring within its functions?

Many thanks
Ethan

April 15, 2008 10:48 am

You’re right… new lenses for digital cameras don’t have the f-stop rings. dSLRs control f-stops and shutter speed via scroll wheels on the camera body. Most lower-end models will have a single scroll wheel located on the grip at the front or rear, while higher end models will have two scroll wheels (front and rear). When in manual mode, aperture priority, and shutter priority, the wheels control the exposure settings. Cameras with a single wheel control both aperture and shutter speed with that wheel and there’s usually some button that you have to push in order to toggle or switch the functionality of the scroll wheel.

Manual focus is also possible, but the dSLR does a poor job at assisting the photographer with it. The focus rings have very short throws (in order to make autofocus faster) and there are no rangefinders built into the viewfinder.

April 15, 2008 12:21 pm

Hi Brian i have a question of what i think applies to depth of field. I would like to know how to make an object that is close to me out of focus and make the object behind that in focus. I have a Fujifilm S700 10x digital camera. It says on the lens: f=6.3 – 63mm, 1:3.5-3.7 , 46mm. When i turn it on shutter speeds go from 4″ to 1000, Apuretures are from f- 3.5 to f-13. Based on any or all of the info i provided can you help me with my question?

July 26, 2008 1:12 am

How do I get big depth of field with Canon SX200 (or Canon SX110 or any point and shoot with manual focus option)., it focuses only on center.

Its highest fstop is f-8. At 28mm I have to focus approx. 3.3m to get max. depth of field.

I have not been able to fully understand how to use manual focus in this case

March 25, 2009 1:35 am


Hi Brian,

I really like the way you explained DOF… I will use your tips when I run a photography workshop for young students next month here in Weimar Germany. Your approach is hands on, practical and informative – Great one! Perhaps as a small tip – it would be nice to see a couple of other examples of DOF from images you have taken – ie: you showed us the Gargoyale in the forground and the building in the background shot at F5.6 – maybe it would be good to also see a couple of alternative comparisons ie: on shot at F1.8 and another at F16 – then – people could get an even clearer idea of why the F5.6 image is probably the best… Kepp up the great work – Cheers – Hamish

June 28, 2009 8:11 am

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