digital photography tips with Digital Photo Mentor Darlene Hildebrandt

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How to use Depth of Field

depth-of-field

If you’ve ever wanted to create images with a beautiful, soft out of focus background this article will give you some tips and guidelines to do just that. We’re going to look at how to use Depth of Field (which is simply how much of your image is in focus) and what settings to use to optimize this effect.

Depth of field is controlled by the aperture setting

Last week we looked at using shutter speed and how it controls motion in your image. For that effect we used the Shutter Priority mode, for creating shallow depth of field we use the aperture so we’ll switch over to Aperture Priority mode.

If you use a Canon you will see something similar to one of these dials on the top of your camera.

If you use a Nikon you will see something similar to one of these:

On a Canon camera you will want to choose the Av (which means aperture value) setting, and on Nikon choose A. That will put you in aperture priority where you will be choosing the aperture setting and the camera will be choosing the shutter speed to make the correct exposure.

Aperture is defined simply as the opening in the lens. It opens and closes just like the pupils in your eyes.

Choose a large aperture opening (small f number) for shallow depth of field

If you want to make a nice out of focus background, and utilize shallow depth of field choose a large aperture opening, the biggest you have on your lens. Aperture settings can be a bit confusing because they are inverse of what you’d expect. The largest aperture opening is actually represented by the smallest number. An example of that would be f1.8 or 2.8. Choosing a small aperture like f22 of f32 will give you a large depth of field where it’s possible to get your entire scene in sharp focus. Each setting has applications in certain scenarios, it’s important to know which aperture to use to get the affect you desire.

Let’s look at some examples

The following images were all shot with an 85mm f1.8 lens (that just means the largest aperture possible on it is f1.8). With such a lens it is possible to get the background way out of focus.

85mm lens shot at f22
85mm lens shot at f16
85mm lens shot at f11
85mm lens shot at f8
85mm lens shot at f5.6
85mm lens shot at f4
85mm lens shot at f2.8
85mm lens shot at f1.8

Notice how different the last shot above looks than the first one! Keep in mind you do NOT have to buy expensive $2000+ lenses to get this look. Sure you can if you feel rich, but if wanna save your pennies opt for a less expensive fixed lens with a wide aperture such as a 50mm f1.8 (less than $150 usually) or an 85mm f1.8 (around $600 or so). I prefer the slightly longer 85mm because, besides using a large aperture, the focal length also plays a part in how much the background gets blurred. Have you ever noticed everything you shoot with wide lens all seems to be in focus? While the depth of field mathematically is actually the same as with a longer lens – the wide makes everything appear more in focus, partly because of distance to subject. When you use a longer lens you have to back up which adds to the background blur as well.

The three factors that affect background blur are: aperture, focal length, and distance of the subject to the background

The three factors that affect background blur are: aperture (using a wide one), focal length (longer lenses enhance the affect), and distance to subject and subject’s distance to the background. You can use the widest aperture, and the longest lens but if you put your subject right up next to the background you’ll never get it blurred. The further away from the background the subject is, the more out of focus you can make it.
Review: compare the images below. Notice how the aperture affects the focus in a drastic manner.

Let’s do one more example, using that subject to background distance factor I mentioned above. In the following images I focused on the tree which was fairly close to me. The background house, yard, etc, is quite a distance away. Let’s see how the same settings we used above play out in this scenario.

85mm lens f1.8
85mm lens f2.8
85mm lens f4
85mm lens f5.6
85mm lens f8
85mm lens f16
85mm lens f22

In this example you can really see how the background starts to come in focus as you close the aperture down to a smaller and smaller opening. Look at the patio and the snow on the railing, compare the first and last images in that area. In the image using f1.8 the snow is so out of focus it has almost started to become circles of white (ironically called circles of confusion, go figure!). Notice how far away that background is, and how widely out of focus I can throw it and have a good result, even using an aperture like f5.6

Here’s a side by side comparison of four of the shots.

What did we learn?

So what can we take away from this experiment? Go out and try doing this yourself. Set your camera on Aperture Priority and run the full range. Make sure then when you get to the smaller apertures (f11, 16 or 22) that your shutter speed isn’t getting too slow for hand holding. If you need to, use a tripod to steady the camera. Don’t let your shutter speed go lower than 1 over the focal length of your lens (so using a 200mm lens you need to shoot at 1/200th of a second or faster to get no camera shake) . I pushed that a bit here using 1/60th with an 85mm lens but it still came out relatively sharp. I could have used a tripod or increased my ISO to give me a bit more shutter speed room.

Practice at home

So DO go try this at home. Try it with something close to the background, then far away. Try it with a 12mm lens, 50mm lens, then a 200mm and see what happens. Share your results in the comments section and please share this article using the social media links below if you enjoyed it.

Related Article

I also wrote another article that is sort of related to this subject, improving your photography. It is called 3 Important Elements of Composition No One’s Talking About and it’s here on Phogropathy.com.

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  • Tim Aucoin

    Great little “reminder” article Darlene! And BTW… you “made me” go ahead and order myself the new Nikon 85mm f1.8 lens… THANKS!!! It will be a nice lens to travel with!

  • Darlene

    I have the Canon version of that, obviously and it a great little lens. Good bang for your buck!

  • Avinash Birambole

    Its a great article…thanks for sharing

  • Dave

    Darlene,
    I shot this photo for the love of sprinklers. little did I know it clearly shows depth of field of focus.
    http://www.flickr.com/photos/kennedystables/8031688591/

    • http://www.herviewphotography.com Darlene

      Nicely done, it sure does!

  • Sandeep

    HI Darlene,
    i’m a newbie to fotography and just recently bought a Nikon 5100 with a 18-55 lens.
    I’ve been very keen to get this blur effect.

    Is my lens too small to get this effect?

    Any guidance on how to do this.

    Thanks

    Sandeep

    • http://www.herviewphotography.com Darlene

      Hi Sandeep – it’s a bit of a shot lens to get that really out of focus affect. Eventually you will want to invest in a longer zoom lens or fixed lens.

  • Rosa

    Thank you so much… i”m learning more and more, thank you for sharing ur article..

  • http://phototechsupply.com Brian

    Thanks for the article, I found it very enlightening and I forwarded it to a friend who I had been discussing that very subject with.

  • Robin

    What lens do you use most commonly for portraits and which one for wildlife/nature/landscape?

    • http://www.herviewphotography.com Darlene

      Hi Robin – if you want to know more about lenses I’d suggest you read a couple other articles I wrote on the subject.

      How to choose the right lens
      How to achieve blurred backgrounds in portraits

      As for nature/wildlife and landscape – those are all 3 very different fields, none of which I do much of. For landscape most photographers use a wide lens. For wildlife you need a really long (like 400mm or 500mm) lens with a big aperture as you can afford. You can’t get close to the animals so you need the big lens to really pull them in tighter. Nature could be anything including a good macro lens for close ups of bits of flowers.

      Does that help?

  • bill butcher

    I was wondering how a crop body camera effects depth of field.I shoot with a 7d ,and it seems that even at smaller APS like f22 the focus is not sharp front too rear, is this do to crop body, or what object in the scene is focused upon?

    • http://www.herviewphotography.com Darlene

      Bill yes it does affect DOF but a cropped sensor generally has more not less. At f22 there is no guarantee you’ll get the entire scene in focus. Yes it also has to do with where you focus. Ideally you want to focus 1/3 of the way in to the scene but that’s pretty hard to measure. Just know that you want to focus closer than mid way.

  • jonno

    Wow i am such an idiot, this was great thanks. You explained what others have been trying to tell me for years. But hey thats me. I will watch your site with great anticipation.

  • Norman

    Hi Darlene,

    Same with few of the guys out here, I am also a newbie and now fond of shooting pictures of my own, though right now I think I’m the only one liking it. Anyways, I have tried blur effects and testing DOF for my lenses but I was wandering what is the big difference of a Canon 40mm f2.8 to a 50mm f1.8 aside from the maximum aperture.

    Also, how can I ever be precise of the right Shutter speed, Aperture and ISO to use for my shots aside from buying an expensive Sekonic light meter, as right now, I’m doing plenty of shots before finally getting the right combination.

    Finally, if you can give me more tips how can I get a perfect shot using less flashes dramatically and elegantly.

    Sorry to ask too many favours and guys please don’t hate me for asking too much, I just want and eager to learn more from experts.

    Regards and thanks

    Sorry to

    • http://www.herviewphotography.com Darlene

      Hi Norman, let me try and attack your questions one at at time.

      Lenses: between the 40mm f2.8 and the 50mm f1.8 you will see a slight difference in how the images look but not much. The main difference is the benefit of having almost 4 stops more light coming into the 50mm. In low light conditions that could be a real advantage.

      For what the lenses do and which one to pick, try reading this article: http://www.herviewphotography.com/2012/10/18/how-to-choose-right-lens.html

      Re precise exposure – I’m not sure I understand your question. Yes you can make a perfectly good exposure using the camera’s meter, and without buying a handheld one like the Sekonic. If you are doing studio lighting with multiple flashes and lights though, it is a lot easier and more accurate to use the Sekonic.

      What do you mean by “I’m doing plenty of shots before finally getting the right combination”?
      In what situations?
      In what mode on your camera dial? Manual? Aperture priority? Shutter priority?
      What is it you feel isn’t working – the look of the image, or the correct exposure (amount of light?)

      As for your last question, that’s a full on weekend workshop, not something easily answered in a comment. And I’d need more clarification on what “perfect shot” means. In what situation? With a person as in doing a portrait? Sorry, I can’t really say in this case there are too many variables and like I said, a really long answer.

      Don’t apologize for asking questions though, that’s how you learn. I just may need more information to help you answer them.

  • Manoj

    Its great for me …I really enjoyed this article.
    Thank you so much..

  • kayjnsn

    What would you suggest be the best maximum distance away from a subject in order to achieve good bokeh at 70mm f/2.8 (in daylight)? Is there a general rule of thumb as to how far away you should be from a subject in relation to focal distance? Thank you!

    • http://www.herviewphotography.com Darlene

      Not really the camera to subject distance is dependant on the lens you use. The longer the lens, the further away you have to be to get the same amount of them in the image. Bokeh also has a lot to do with how far away the subject is from the background. If they are 1-3 feet away from something you won’t get any, but put them 20 feet or more away and you’ll get a lot more bokeh. Does that help?

  • fourteen14

    The focal length does not affect depth of field. F:8 is f:8, is f:8. Longer focal length lenses foreshorten the relative distance between objects in the background. An example is a series of street signs look closer together with a long lens than they to with a shorter lens.
    If the field of view is the same for a short lens and a long lens, then the DOF is exactly the same. Distance from the subject for the same lens at the same f:stop is different. The closer (by physical distance) you are to a subject means that more of the background is out of focus as IT is farther away from the subject.
    I think that photographers have to learn and understand the focal properties is the various lenses. I know friends of mine use to spend days or even a week choosing a lens for a particular scene not only for colour, but for its focus and dof properties.
    Practice, shoot, focus and try different f:stops to discover the “look” of the lens/lenses you own. I’ve gone through so many lenses, the guy at Henrys loves to see me come in to the store. My lenses are also rear-focus because these do not show a change in image size when shifting focus for video work.
    I’ll stop now before this becomes a book. Get to know your lenses and follow the light.

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