Seeing in Depth of Field: A Simple Understanding of Aperture

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Photography can be simply defined as: painting with light.

When you are painting with light, you are creating a story in a split second. That’s what photography is all about. Technically, your camera is measuring the light in the scene, and you are telling it how much of that light you want to use to create a properly exposed image. This becomes your story.

There are three main settings used to control that light; Shutter Speed, ISO and my favorite, Aperture. Each of these settings has its own individual way of measuring light. When all three are balanced correctly, you create a proper exposure.

1 Aperture Range 3265

Though each of these three settings measures light, they also have unique characteristics that create artistic qualities in your photographs. By understanding them, you have control over the full story you want to tell.

Shutter speed captures movement or freezes it. ISO helps control how sensitive your camera is to the available light in a scene. Finally, the aperture creates depth of field. This is where the real story comes from; it is with aperture that you control what is in focus, and what is out of focus.

As a photographer, how do you decide what you want your viewer to focus on? How do you create a story? That’s what aperture is all about, and that’s why I love it.

WHERE IS IT AND WHAT DOES IT DO?

Aperture is located in your lens, not in the camera body. The lens opening expands and contracts to control light. By selecting a specific aperture size, you are telling the lens how much light you want to hit, and register on, the sensor.

It is very similar to how the human eye works. Your pupils expand and contract based on the available light in the scene. Like when you first walk into a dark movie theater. At first you can’t see, then your eyes adjust. Your pupils expand, allowing your eyes to see as much light as possible in the dark room.

Again, when you go outside on a sunny day, at first it’s too bright to see. Your pupils adjust by contracting, letting in less light. Your lens aperture works the same way. Changing aperture settings is like your pupils dilating or contracting.

The size of a lens aperture is measured in what we call f-stops (fractional stops). Just like all settings on a camera, there is a general range.

2 aperture range2

The numbers aren’t necessarily important to memorize. What’s important is to see the range in the settings. Here is the trick; the smaller the f-stop number (like f/1.8), the larger the aperture opening. This means more light will enter through your lens at once, and vice versa. The larger the f-stop number (e.g. f/22), the smaller the aperture opening, and less light will enter your lens.

Think of these f-stops as fractions. Just replace the F with the number one. 1/4 of a pie is much more than 1/16 of a pie.

A quick note: Not all lenses are built the same. Different lenses have different apertures. Some lenses have a wider range and some have less. Standard lens will range from F3.5–F22. Specialty lenses go as low as F1.2 or more. See: What the Numbers on your Lens Mean for more on this.

SEEING IN DEPTH OF FIELD

Here is where it gets fun. While measuring light, when the lens expands and contracts, it also measures depth of field. Again, your eyes do the same thing!

As you look at the screen to read this, these words are mostly in focus to your eyes. In your peripherals, you can see other things, but they aren’t in focus.

Notice, your hands on the keyboard, they are in the foreground, and perhaps a bookshelf is in background. You can see them but they are not in focus. You are seeing in depth of field.

A great photograph does just that. It captures a foreground, a mid-ground and background. By setting your aperture you are controlling which of these areas is in focus. It is all based on your intention, your story.

DEFINING DEPTH OF FIELD

With your camera’s focal point (that little square in the middle of your viewfinder), you focus on a particular part of the scene. This point becomes the sharpest part of your image. There is an area in front of that point in focus, and an area behind it in focus as well. The distance from front to back that is acceptable focus is considered your depth of field. You decide what is acceptable by choosing a specific aperture size.

3-Uluwatu-Monkey-8427

This is a story about a monkey on a cliff. The bushes in the foreground and the temple on the cliff in the background are out of focus. They are out of the depth of field. This brings your attention to the focal point; the monkey in the middle (no pun intended).

Remember, the lower the f-stop number, the bigger the opening, the more light comes through the lens. This means less of your scene is in focus and you have a shallow depth of field. The opposite is also true. The larger the f-stop number, the smaller the opening, the less light comes through the lens. In this case, more of your scene is in focus and you have a greater depth of field.

Simply put, the larger the f-stop number, the more will be in focus. The smaller the f-stop number, the less well be in focus.

A DEEPER LOOK AT DEPTH OF FIELD

As you lock your camera’s focal point on a specific spot, that spot creates a focal plane. Everything that is the same distance away from the lens is on the same focal plane, and will be in focus.

4 focal plane explained

At a shallow depth of field (low number), the focal plane is very thin. As your depth of field becomes greater (high number), the focal plane becomes deeper.

Here is the same scene photographed with different aperture settings. Notice that the depth of field changes how much of the image is in focus.

5 aperture example

At f/2.2 only the sunglasses are in focus. At f/5.6 the hat is also in focus. By using f/8.0 you can start to make out the trees in the background. Finally, at f/22 everything in the image is in focus.

Which one tells the best story? You as the photographer, get to decide.

PRACTICE TIPS AND TRICKS

Now that you’ve got a good grasp on the basics, it’s time to play! Here are some great tips to start your practice.

Set your camera to Aperture Priority mode. You will have full control of the aperture, without having to worry about proper exposure. This way you can just focus on depth of field. It’s a great way to fully understand what your lens is doing as you change your aperture settings.

Pick a subject or scene, and stick with it. Photograph your scene from many different angles. Choose different parts of the scene to focus on using the full range of aperture settings.

Use these guidelines to capturing depth of field in different scenarios:

6 Aperture Range 9748

When shooting single subjects, like a portrait of a child, it is best to use a lower f-stop like f/1.2-f/2.8. Creating a shallower depth of field brings attention to the subject’s face, which is always most important in a portrait.

7 Aperture Range 2145

When shooting a small group of people (2-5), choose an aperture of f/4-f/8. This, being a slightly deeper depth of field, guarantees that everyone in the group will be in focus.

8 Aperture Range 6150

Any time you have a wide-open scene, for instance a landscape, and you want all of that landscape in focus, choose a setting above f/10.

These are just guidelines. Photography is a form of art. Be creative, and remember, it’s all about telling a story.

What story do you want to tell? Share your images here and show how you’ve used depth of field to create a great story.

All Images in this article are © 2015 Danielle Werner and DEW Imagery & Design

 

Read more from our Tips & Tutorials category

Danielle Werner is a free-spirited photographer, designer and retoucher, on an endless journey around the world. She is also a passionate writer and educator who teaches photography workshops wherever she goes. Read Danielle's inspirational travel stories at LiveWonderful.com, and check out more of her adventure and lifestyle photography at DEW Imagery & Design.

  • This is the best explanation I have ever seen about aperture. Even a photography dummy like me can understand. Thank you so much!

  • This is wonderful to hear! My entire purpose as a passionate photography teacher is to let the light bulbs go off and empower you to feel great about what you are learning. Let me know if you have any questions as you start practicing!

  • David Thompson

    It’s a well done introduction to depth of field. This is a complex subject that confuses many photographers and is a kind of hot button of debate. So, it’s refreshing to see a simpler treatment of the topic that is an excellent introduction without all the technical jargon. Thank you.

  • David, I absolutely agree with you. This is a hot topic. And it can get confusing with the technical jargon. Thank you for pointing this out. It’s important to me that as I teach the fundamentals of photography in my workshops and online, that it’s easily understood, there is room for “ah-ha” moments and encouragement to go deeper into a specific subject as the learning continues. I find that simple is always better! Let me know how this article helps you develop your view of DOF in the future.

  • I totally agree with your advices on this article, Danielle, and the images posted exemplify perfectly the points you mention!
    When I bought my latest lens last winter (a typical portrait lens, equivalent to 85mm and with a fast, bright aperture) I really understood how to play with aperture on a more “physical” way, since this is my first lens with an aperture ring, which has taught me to use the camera in Aperture priority, as you suggest, and just play with the aperture to get the desired depth of field. I’m enjoying photographing on a whole new level now, having so much control over what parts should be in focus and which ones not!
    You can see some pictures I took in the small village of Mae Sot, in the border between Thailand and Myanmar, where I did just that: http://gonzalobroto.blogspot.com/2015/05/mae-sot-border-city.html

  • Gonzalo, what beautiful photos you’ve made! I’ve been traveling throughout SE Asia for 6 months now… your photo post is inspiring! Thank you for the compliment. You’re right, it’s a whole new level of photography when you get the aperture thing down. Now, we get to take risks and create an entirely new “lens” to view the world from 🙂

  • Miss Cathy

    This article was so helpful, and easy to understand. I normally shy away form using aperture priority mode, but after reading this am definetly going to practice more with it. Thanks for sharing.

  • Miss Cathy, first of all, thank you for reading! Second, I’m proud of you for taking the leap to committing to practicing. That’s the first step! When you practice in aperture priority, be patience with yourself and explore your subject from many angles and close up and far away. Let me know when you have an “ah-ha” moment while reviewing your shots. It’s the best feeling. And if you have any follow up questions, feel free to ask.

  • David Thompson

    Morning Danielle… By profession, I am an engineer and am technically inclined. So, after reading a lot of opinions about depth of field, I spent a few hours analyzing the relation between focal length, medium size, sensor/film size, aperture, and distance from subject to sensor. It was fascinating to look into these topics and I learned quite a lot and think I understand, now. There is no equivalent to putting pen to paper and working through a problem to gain insight.

    I began a monograph on what I learned and will return to it later this summer. The monograph is technical, but the conclusions will be straightforward. Those who are mathematically inclined (algebra) will have everything they need to understand the technical basis for my conclusions. Those who are not technically inclined can trust me. 😉

  • Dominic Bolaa
  • Hishe1966

    < col Hiiiiiii Friends… check it now …. ++photography+ + SEE FULL INFO

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  • Themba

    Thank you for this simple to understand lesson. I was itching to get on with the playing part only to realize that my camera is the automatic type! I hate it already that I can’t practice what I have just learnt from your article!

  • Miss Cathy

    Thanks Danielle i would definitely let you know the moment i go “ah-ha”. And ask any follow up questions. Thanks again.

  • lilia

    thanks for a great post! I’ve been working on my photography for about a year now but still wasn’t sure of general guidelines for aperture especially for things like small groups – this was helpful. and that last photo – where is that?! I want to go there!

  • Stoffers

    Just curious, how do you normally shoot?Is there a reason you haven’t used Av more?

  • So glad this article was so helpful for you! It’s always great to have that feeling of moving up to the next level of learning! That last photo was taken last winter during a road trip through Europe. It’s a “small” lake in the valleys of Switzerland close to the borders of Italy and Germany. You can see more adventure photos like this one (and stories too!) on my blog, http://www.livewonderful.com

  • Aw darn it! What kind of camera do you have? If its a newer digital, there is a possibility to “hack” the brain of your camera and trick it to do things! Thank you for reading!

  • Thanks Danielle!

  • Marko Leus

    I quite appreciate the comparison with a pie to remember that a smaller number means a larger aperture (as i quite appreciate a pie ;-)). Thanks!

  • Yay! Thanks Marko, I like that trick too. Even as a pro, the pie is in my mind 😉

  • thank you for sharing it. 😀

  • Tim Lowe

    I think it is important for beginning photographers to understand that SLR/DSLR lenses allow for composition and focusing with the brightest possible image. To accomplish this, the lens is always stopped down for composition. The lens changes to the selected aperture only during the actual exposure. But almost all lenses allow a depth of field preview either by pressing a button (on a more modern camera) or on the lens (as is the case with all my medium format Zeiss lenses.) While this probably darkens the image in the viewfinder, it is often a good check for the photographer.

    Also, those of us who use manual focus lenses have the added benefit of having a depth of field guide on the barrel of the lens itself. This is either in the form of stationary pairs of marks corresponding to the lens aperture and a distance scale that moves as the lens is focused OR (as is the case with my older Zeiss lenses) a pair of moving needles that move as the aperture is changed and the same distance indicator on the focusing ring. This is very helpful when managing the DOF of a given shot. Focusing the lens at infinity wastes half the DOF, placing beyond infinity and pulling the focus in from infinity can greatly increase the effective depth of field in a given image.

    I’m sure you could explain this to novices better than I have here. 😉

  • Josh

    I think it’s very important to discuss distance to focus point when trying to teach people about aperture and DOF. It so often overlooked when written about in similar articles, but a very important aspect of the whole concept. You can be at the same aperture and move closer to your subject narrowing your DOF…Moving further away gives the opposite effect.

  • Jeff Crozier

    Really found this helpful. I am just starting out as a photographer and I am learning about aperture, iso and shutter speed. This really brought clarity to the jumble of numbers and settings. ha ha Thanks!

  • spalady

    So when you shoot aperture priority is your camera choosing the shutter and ISO or are you shooting fully manual?

  • Philnick

    Generally a good explanation, but you repeatedly use the word “measure” to mean “control.” Those numbers may be measures of where in their ranges a camera’s settings are, but what you’re explaining here is how they control the image’s appearance.

  • Philnick

    Aperture priority means you set the aperture and the camera chooses the shutter speed, based on the light level and the ISO you’ve set. Only fairly recent cameras even have Auto ISO, which lets you choose both aperture and shutter speed, with the camera adjusting the ISO. Before you use that mode you should put limits on how high an ISO it can use – to avoid winding up with noisy pictures at very high ISOs. Experiment to see how high you can set the ISO before the noise is objectionable to you.

  • Moshy Pipes

    Thank you so much, i went out i tried it and am loving it

  • Thank you Philnick for this feedback. You are correct. As it’s my first time writing about such a technical subject, I do find it to be a challenge to have the absolute correct jargon. I am learning just like everyone else on this awesome website. I will be sure to keep this info in mind as I write my next article.

  • Philnick as done a great job explaining the difference between Manual and Aperture Priority modes below. Thanks Philnick. >> You should write for DPS!

    Spalady, you can also check out this article written by Darlene. She explains it simply and with photos 🙂 Good luck with your practice.

    https://digital-photography-school.com/getting-off-auto-manual-aperture-and-shutter-priority-modes-explained/

  • Jeff, I am so glad to hear this! It was an eye opener for me when I first started. Although, it took me years to find a great simple explanation to share in my teaching. Good luck with your practice!

  • Josh, I agree. It is important to discuss distance here. I’ll have to consider writing a follow up article that goes deeper into this subject. I’m seeing some great feedback and with photos! So this is definitely a great start and a big eye opener for the beginners reading to learn. Thanks for your feedback.

  • Hi Tim,

    This is a great explanation. However I think that this is a level two subject. Many of the readers of this article are getting great first time results when before they were unaware of the basics of Aperture. I am happy to see “ah-ha moments” or “light bulbs” going off! Maybe I can write another article that goes deeper into this subject for those who are ready for the next step! Thanks for the feedback.

  • This is so awesome! Great photos! The birds are beautiful! You definitely have the hang of this! Consider reading the comment below from Josh. He’s described a very important aspect that I know you are ready to learn next:

    Josh writes,
    “I think it’s very important to discuss distance to focus point when trying to teach people about aperture and DOF. It so often overlooked when written about in similar articles, but a very important aspect of the whole concept. You can be at the same aperture and move closer to your subject narrowing your DOF…Moving further away gives the opposite effect.”

    Overall, Moshy, you have definitely stepped it up! Great work. I see you love nature, its such a perfect subject to practice this with. Next challenge, moving subjects 😉

  • abhijeet joshi

    Tried to take pictures with diff. aperture values. One of such pictures is attached here. Request your suggestions / critics wich would help me improve my photography

  • This is wonderful. You definitely have the hang of Aperture. What post processing program are you using? My suggestion is that as you continue to practice, when you load the images to review in post, study the settings for each. Compare the great images to the not so great and start to analyze what you feel makes the image great. It could be that one such subject looks more impactful at a shallower depth of field. Or it could be the composition. Those settings become easier to identify as you study more and more. I am guessing this was image was taken between f2.8 and f1.4 , am I correct? Great job, keep it up!

  • abhijeet joshi

    Thanks for your comments. Very encouraging
    Above picture taken at f3.5
    Attaching another pic for your review

  • Shiralee Merrick

    Comments welcome for this photo.

  • Leonard Schrock

    I think where Tim Lowe says ‘the lens is always stopped down for composition’ is a mistake. I think it is wide open which is not stopped down.

  • Moshy Pipes

    thanx to you Danielle, your article was on point

  • Edmund

    The stamen is out of focus and, like a person’s eyes in a portrait don’t you think that is the most important part of this image?

  • Edmund

    That’s what chimping and spray and pray are for.

  • Edmund

    In general, for any given focus, depending on aperture, focal length of lens and size of sensor, 1/3rd will be in focus in front and 2/3rds behind the actual point of focus.

    So, on a full frame camera with an 85mm lens at f8 focussed at 6ft you might have a depth of field from 4ft to 10ft with the pin sharp point at 6ft. Hope this makes sense.

  • Tim Lowe

    Both cured by film photography. 😉

  • Janet

    Here’s a few from when I first got my DSLR and hadn’t learned how to use it. These examples are with a 60mm macro lens- different results compared to non macro. The lizard is at 3.2, Acadian Hairstreak(butterfly) on common milkweed at 4, and the milkweed beetle (which is not the greatest technically- I plan on recreating that shot) is 4.8.

  • abhijeet joshi

    Thanks for the comment ! I will try to improve on that

  • David Thompson

    You are correct. This is an optical property and you can prove it using the thin lens formulae. It’s approximate, but close enough for all practical purposes.

  • David Thompson

    I think so too, Edmund. Your comment reminded me of one of the things I like about mirrorless cameras (always in live view). It is that as you stop down for a focus preview, the finder does not go dark. That used to frustrate the heck out of me when trying to confirm focus and depth of field (in the viewfinder).

  • Miss Cathy

    I shoot mainly in manual mode, and i guess a lack of understanding never let me use aperture priority mode.

  • Great macro shot Janet. I’m only seeing the shot of the butterfly – eyes in sharp focus. This is key, especially at such a shallow depth of field. Where do you want the viewer to focus? You’ve done a great job of making this image impact the viewers perspective of what it’s like in a butterfly’s world!

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