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The Four Factors that Affect Depth of Field

By Tanya Goodall Smith on March 23rd 2016

Last week, Max Bridge included me in his article entitled 7 Mistakes From Professional Photographers That Held Them Back. I wrote about the fact that it took me so long to learn about how aperture affects depth of field, and once I figured that out, a whole new world opened up for me photographically. I later learned that other factors, like the focal length of a lens and the distance between the lens and the subject and the subject and the background, also affect depth of field.

I’m guessing some of you are in the same mode of discovery I was in a few years ago, so I’ve compiled a bunch of resources to help you understand the four factors that affect depth of field. Wikipedia defines Depth of Field in optics, particularly as it relates to film and photography, “as the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.” What in the heck does that mean? Let’s find out by exploring the four factors that affect the depth of field in your image.

1. Aperture (a.k.a f-stop)

Aperture is one of the easiest ways to control your depth of field. It’s why photographers love lenses with a 1.2 maximum aperture. Open your aperture all the way to 1.2 and you’ll get that creamy bokeh (blur) we all love in the background. The gif animation above illustrates quite well how aperture affects depth of field, or as the definition above says, how many of the objects in the scene will appear to be in focus. For a shallow depth of field (at a wide open aperture, f/2.8), only a small plane of the image will be in focus, like the one toy in the middle there. With a wide depth of field (and a closed down aperture, f/22), almost the entire image is in focus. Make sense?

Joe Gunawan (a.k.a. fotosiamo) goes into more depth about the differences between shallow and deep depth of field in his article Aperture Guide Part 2: Shallow and Deep Depth of Field. Check it out!

2. Subject to Camera Distance

The closer your camera is to your subject, the more shallow depth of field you will have in your image. Pull your camera far away from your subject and more items will be in focus, even when using the same aperture. Here are two great examples from Joe’s article mentioned above.

In this image, yes the aperture is at f/2.8, which will help us get that blur in the background, but the camera is also right up close to the subject, which allows the foreground to be in focus and the background out of focus.

In contrast, this image was also shot at f/2.8, but since the camera is far from the focal point (the bride and groom) much more of the image is in focus, including the first several rows of people in the congregation.

depth of field

On a related note, the distance of your subject from the background will also affect how much bokeh you’ll get in the background. This is one reason I often have my subjects step away from a fence or wall if I want some blur back there. In this image, my subject is standing right up against the wall, and it is relatively in focus. This was shot at 70mm, f/2.8.


This image was also shot at 70mm, f/2.8 but I had her step several feet away from the wall, which results in a nice creamy blurred out background. I love it! By the way, neither way is “better,” just different depending on the look you are going for.

3. Lens Focal Length

Did you know the focal length of your lens will also affect your depth of field? I didn’t realize this until a few years ago. This is one reason portrait photographers love their 70-200mm massive lenses. They can get some amazingly shallow depth of field when shooting at 200mm. In contrast, landscape photographers shoot with wide angle lenses, not only so they can fit more in the scene, but so they can achieve sharpness in the maximum amount of the image as possible.

In this example, the image is shot with a longer focal length lens (100mm). Even though the aperture is closed down to 7.1, since the focal length is longer, the background is compressed and blurred out. Man, this makes me want to go out and buy the Canon EF 100mm f/2.8L macro lens right now!

In this example, at the super wide angle of 17mm, most of the image looks pretty sharp. This is surprising since you would think you would need to have your aperture at a lower number like f/11 or f/22 in order to get an image to be this sharp. You can see how much the focal length of the lens really affects depth of field here.

4. Camera Sensor Size


Camera sensor size is a factor affecting depth of field that I honestly hadn’t given much thought to until I was doing research for this article. Our Photography 101 Workshop goes into detail about crop vs. full frame camera sensors and what that means. In regards to depth of field, basically, the bigger the sensor, the shallower the depth of field will be overall, when taking all the other three factors into consideration. This is why, when I upgraded from a Canon Rebel to a Canon 5D Mark III, even though I was using the same Canon 50mm f/1.4 lens, I noticed I was getting a much shallower depth of field when shooting wide open with that lens on the new camera. It was so dreamy and exciting!

This is also one reason landscape photographers sometimes choose to shoot with a crop sensor camera. When overall sharpness and deep depth of field are desired, a smaller sensor can help achieve that.

Additional Tips and Tricks


When you want shallow depth of field but you’re using strobes, you might have a problem with overexposure. Learn how to utilize a Neutral Density (a.k.a. ND) filter to correct your exposure using strobes while keeping a shallow depth of field. It’s like putting sunglasses on your camera.


Missing the focus when working with a very wide open aperture is a common mistake photographers often make. Learn how to overcome that hurdle with these specific tips offered by Max Bridge in this article about nailing focus with a narrow depth of field.


Let’s say you’re shooting at f/22, the maximum aperture of your camera, and your entire image still isn’t in focus? What can you do to achieve massive depth of field? Gavin Hardcastle offers three solutions and some incredible photo examples in this article. His three solutions are:

  1. Choosing the right aperture and focusing carefully
  2. Focus Stacking
  3. Using a Tilt-Shift lens

Any more questions about depth of field? Leave them in the comments or check out our Photography 101 Workshop, which covers all the basics of composition (including depth of field), exposure and the other functions of your DSLR.

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Tanya Goodall Smith is the owner, brand strategist and commercial photographer at WorkStory Corporate Photography in Spokane, Washington. WorkStory creates visual communications that make your brand irresistible to your target market. Join the stock photo rebellion at

Q&A Discussions

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  1. Carey Smith

    Very informative.

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  2. Shawn Kelley

    Where is hyperfocal distance in this sandbox of factors? ;-)
    Another article, perhaps. It’s quite deserving considering the landscape photography references.

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  3. Marc Billingsley

    I wish you hadn’t mentioned “sensor size” as a factor. If you want to get SUPER technical, a crop sensor actually has a slightly MORE SHALLOW depth of field than a full frame sensor. However, the field of view is clearly different. So, if you are trying to get the same field of view (example: head and shoulders only) of a subject, then you will be closer to the subject when using a full frame sensor. This makes many falsely believe that larger sensors have more shallow depth of field….however, the truth is that it’s the distance to the subject that has changed and makes the full frame camera SEEM like it’s a more shallow depth of field. Technically, it is the opposite (very slight difference).

    So, no, full frame sensors are not more shallow DOF. They simply make you get closer to the subject for the same field of view….the act of being closer to the subject is what actually is changing your depth of field…. not the sensor size.

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  4. robert s

    5 factors- subject to background

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    • Marc Billingsley

      This is still really distance to camera. The farther the background is from the lens, the more shallow…….

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    • robert s

      no. I can keep my distance the same to the subject and walk back and tell the subject walk with me away from the background and get more blur. if I put that subject on a wall, no matter how much I move in closer or shoot wide open, the wall will be pretty visible and easy to make to your comment, no its not.

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    • Marc Billingsley

      But that is STILL distance to camera. You are moving farther away from the background, so it’s distance to camera. The term “subject” doesn’t just apply to the person…. the entire frame is the subject of the camera.

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    • Nick Viton

      Already mentioned under #2. Did you read the article?

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    • Barry Chapman

      The heading for #2 is Subject to Camera Distance. It would have been better to label it Subject Distance to Camera and Background.

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    • Peter LaGregor

      moving subject to background doesn’t change the depth of field, it just moves the background out of the DoF.

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