Tuesday, May 3, 2011

Depth of Field in a nutshell!!!!

Depth of field in a nutshell.....

So, have you ever wondered how to get blurred backgrounds when taking photos of a person. Have you ever wondered how professional landscape photographers get their shots so sharp?  Well, You are about to learn how to control what is in focus and what is not when you are taking a photo. You will also learn when it is appropriate to used small aperture versus large aperture.

To start out you need to know what an aperture is.  Basically, an aperture is a hole in your lens that controls how much light hits your camera's sensor. An aperture works like the pupil of your eye.  To test this theory, go into your bathroom( I know, I could tell a joke here, but I won't) and look in the mirror.  Look at the size of your pupil.  Now turn off the light and wait a few seconds.  Quickly turn on the light and your pupil will be larger.  As your eye's adjust, your pupil will become smaller.  The aperture in your camera works the same way.  When you are in a low light situation, the aperture  needs to be larger to let in the correct amount of light( your shutter speed also controls this, but that is a different lesson). When you are shooting
on a bright day, you aperture needs to me smaller.  Got it? If not leave a comment so I can clarify more.

Anyhow, apertures are given numbers to help with standardization.  F/2 is a large aperture(lets in lots of light) and F/22 is a small aperture(lets in a small amount of light).

Here is a basic scale of apertures:
f/1.4,f/2, f/2.8,f/4, f/5.6, f/8, f/11, f/16, f/22, f/32

Most lenses these days start around f/4 and go to f/22, but high quality lenses can go further. They are usually more expensive(not alway, but most of the time).

So what is so cool about a lens that goes to f/2?
Well, f/2 will give you shallow depth of field.
On the other end of the scale, f/22 will make almost everything in focus.

Let me show you what I mean.

This shot was taken at f/2.
It has shallow depth of field 

This shot was taken at f/8.  
See, more of it is in focus.

This shot(above) was taken at f/16(on the lens I used this was the smallest aperture).
Now, almost everything is in focus.

So, how do you use this in everyday photography you ask?

If you are taking a photo of you kid outside at the park and there is a lot of distracting stuff in the background(like weird looking parents and some goofy guy) you will want to use a f/4 or f/5.6.  This will create shallow depth of field so the background will be out of focus.

If you are shooting a close up portrait, you will probably want to use f/8 so that your subject is in focus and the background is still blurred. For a long time most portrait photographers always shot at f/8, but in the last few years this has changed.  You can decide for yourself how you feel about this.

If you are shooting a landscape, you probably want to use f/22 so everything is in focus and sharp!

Notice that I said probably in all the senerios above? There are always exceptions.  As you become more advanced you will get better at choosing the f/stop that is appropriate.

Just a note: when you are using a small aperture(f/11-f/22) you might need to use a tripod because at small apertures you have to use a longer shutter speed.  We will talk about this soon.

P.S.  Comments are appreciated!!!



  1. I am a beginning photog and I am just experimenting with the manual/creative modes on my canon rebel eos. I thought your explanation of dof and apertures was clear, concise and very easy to understand. Thanks!

  2. Thanks for the comment!! That is exactly what I like to hear! You made my day! Thank you , Thank you, Thank you!!!

  3. Sorry I'm late w/ this comment... but someone told me a hint: how many people in the photograph determined the F factor. One person is going to be the 1.4 (or 1.6, etc). Five people will be a higher number, and say you have like 10 people, it'll be the highest number. That's the only way I can keep my numbers straight!!

  4. Just starting out with photography and found the examples of different apertures very helpful! Thanks!

  5. Clear and concise explanation, really well done.
    What are your thoughts on diffraction at very small apertures?

  6. Jim, Thanks for the comment. When it comes to diffraction I don't really worry about it. Lately I have been doing a lot of portraits so I shoot wide open. When I shoot landscapes I usually use f/16 and f/11. I know that diffraction can lower the resolution of your photo and obviously that's not good but it's also something I can't really do anything about. I just don't worry about things I can't control.
    Jim, you sound like a smart guy, but for those of you who are reading this and don't know what we are talking about you call follow this link to understand what we are talking about! Thanks again Jim.

  7. Nice article. I am following you on Twitter as well.

  8. Thanks RobmitchSr! I appreciate that!!

  9. Love how you explain f/ stops. Very well said. And your example photos truly show how different each f/stop is. My instructor would just adore you.

  10. Hey! Thanks a lot for this info, it was so useful for me. On the other hand I'd like you to talk about the shutter speed you were talikng and also about the "A" and the "S" modes on the camera. Thanks. Sorry about my english haha!

  11. Anyone would agree with me that there is no easier way to explain DOF than the way you did. Thanks for been so clear and easy to understand.

  12. Thanks for the clear explanation, Brian. I'm new to using manual or partially manual settings on my camera, and I'm really trying to understand how best to set aperture for my shots. I understand what DOF means, but I still don't have a good grasp on how to estimate what aperture will be best for each situation. Is there such thing as a chart or diagram or something that would give me examples of various scenarios? If I can go from f/1.8 to f/32 (diff lenses of course) how can I estimate my results at f/8 vs. f/11 or f/22? or even f/32? What I mean is, what kind of distances are we talking about at each f-stop? Close up is one thing, but once I'm looking at a greater distance, I'm a bit lost.

  13. Trixie, I am not aware of any charts that will give you a general idea of what will be in and out of focus. I am sure they are out there somewhere, but on older lenses, and some newer ones there are guides on the lenses themselves that give you the info. However on most new lenses these guides are gone. But, on most cameras there are Depth of field preview buttons. When you press the depth of fiend button the lens "closes down" and will give you a good idea of what is in focus. There are general guidelines on what to use for certain situations though. If I am shooting a landscape I usually use f/22. If I am shooting a family I usually use f/11. If I am shooting a portrait I usually shoot wide open at f/1.4 or the widest aperture on my lens. Anyhow, if I were you I would practice and get to know what your lenses do and then you can make an educated guess when shooting. anyway, hope that helps. I appreciate your quesition.

    1. Hi Bryan, would you mind DM'ing this link to me so I can test on my canon tomorrow .. I'm on my phone at the mo ! Explanation is perfect by the way! @mariaclewis

  14. Am a beginner photographer and I have learnt a lot from you,wonderful piece. rather unfortunate I don't own a dslr now.

  15. You are great source of information and inspiration to me,am an aspiring pro photographer and your materials are very vivid and useful. Great job sir

  16. Any chance (and apologies if I've missed it) of the same great overview for taking pictures of motion - like capturing the motion of water running and also the blur of moving car lights...would love to get some tips on this!

    Fab tips by the way! So easy to follow. Thank you so much!

    1. Kristy, Yes I do have some posts on blur and moving objects. however I will do some newer posts soon on these subjects. Thanks for the comment!

  17. i've been visiting your site for a week now and i already learned a lot.thanks.