Step by Step Guide to Aperture

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Aperture is probably my favorite setting to play with. You’ll see why when I explain more! I’m creating a manual blog series to help you understand the different aspects of manual mode. As well as a manual mode course, which is currently in the works! I’m so excited about it and I feel like I can help a lot of people (best of all, it’s going to be fairly cheap. 😀 ) This is a little glimpse into what the course will have to offer. I’ll also be including SO much more (like videos, cheat sheets, guides, examples, PDFs, etc!). This course will air in November of 2019!

Let’s talk about aperture in this post. I’ll try to explain in full depth everything you need to know about aperture!

Step by Step Guide to Aperture

what is aperture

Aperture is a hole within the lens that opens and closes to allow light in. It’s easy to understand if you think about how your eyes work, because it’s exactly the same thing! As you move your eyes between dark and bright things, your pupil will expand or close depending on how much light is being let in. In photography, the ‘pupil’ is the aperture. You can expand or close the aperture to let more or less light in.

Aperture has a few different effects on your photos. By going with a wider aperture (this will be a lower number), you let in more light, meaning your image will become brighter the wider you move your aperture. If you go with a closed aperture (this will be a higher number) you let less light into the camera’s sensor meaning the image will become darker.

Along with it becoming brighter or darker, you also introduce depth of field with aperture. Depth of field is the amount of your photograph that will be ‘sharp’. When you have a wider aperture (lower number) you introduce more depth, meaning less of your image will be in sharp focus. This is how you blur out a background.

I know when I first started, I was always curious about how other photographers got a beautiful blurred out background. Because when shooting in auto mode, I almost always had tack sharp backgrounds. And I thought it looked really bad! So, I learned manual mode. 🙂

If you want more of your image to be in focus, then you would want your aperture to be closed down (higher number). This is especially helpful in landscape and macro photography. Whenever you would want most of your image to be in sharp focus.

aperture examples

Let’s take a close look at some examples of what aperture looks like. Paying close attention to the setting that looks like: f/#. That is the aperture setting. Notice that the bigger the number, the more things are in focus in the image.

85mm | ISO 125 | f/1.4 | 1/250 ss

85mm | ISO 500 | f/3.5 | 1/200 ss

Aperture in Photography

85mm | ISO 1600 | f/6.3 | 1/200 ss

Aperture in Photography

85mm | ISO 3200 | f/10 | 1/125 ss

Aperture in Photography

85mm | ISO 6400 | f/16 | 1/80 ss

Like I said above, the wider the aperture (smaller number) the more light and depth of field there is. Meaning, more blurry background.

Are you still struggling getting a blurry background? Check out my post about how to achieve a blurry background!

aperture and depth of field

Depth of field refers to the part of your image that is in focus. Depth of field has a few factors to consider, such as how far away you are from your subject, how far your subject is from the background, what focal length (lens) you are using, and your aperture will all play a part in depth of field. It really depends on the type of look you are going for. If you want everything in your photo to be in focus, you would most likely have a closed down aperture (larger number) and have your subject be very close to the background. This would make it so that the background is in focus as well as your subject.

But first, let’s talk more about depth of field. Basically, depth of field is the zone or plane where your image is in focus. This zone will change from picture to picture. Some images might have very small zones of focus which is called a shallow depth of field.

You usually achieve this shallow depth of field with the following things:

  1. Wide aperture (small f-stop number)
  2. Subject is far away from the background
  3. What lens you use

Let’s take for example you are photographing two children in a field. You’re using your 85mm 1.4 lens and you have the children on the same plane (they are cheek to cheek!). If you were to use a pretty wide aperture, say f/1.8 and the background was far behind your subjects and you were far away from your subjects, your subjects should be in focus. However, I like to usually play it safe and have the aperture at f/2.5 or a little higher. You’ll still get a nice blurry background, but you’ll ensure that both subjects eyes are in focus. This is very important when choosing your aperture.

You don’t want one eye to be in focus and the other not be in focus.

how to achieve bokeh

First of all, what is bokeh? Bokeh is the out of focus part of your image that is created with light and blur. It literally translates form Japanese to ‘blur’. Bokeh has been defined as ‘the way the lens renders out of focus lights’. Bokeh helps create visually pleasing images.

Below is an example of an image with really nice, lovely bokeh. See all of the little ‘dots’ of light in the trees? That’s bokeh. And that’s what you want to achieve in your images (well, not all the time, but sometimes!).

Step by Step Guide to Aperture

Here’s the best way to achieve bokeh:

  1. Use the right lens – by that I mean one that has an aperture of 1.8 or lower. If you have a lens that is 1.4 or even 1.2 – you’ve got it made! But, that being said, there are other ways to achieve bokeh without those drool worthy apertures. Let’s discuss them some more…
  2. Put your subject far from the background – if you are looking to ‘blur’ out the background, you should be doing this anyways. The farther away you put your subject from your background, the more blur you will introduce. If you have a wider lens (for example, the above shot was taken with my Sigma 24mm 1.4 lens, a wide lens) then you will need to be very far away from your background in order to introduce a good blur. If you shoot with a more telephoto lens (I have the Sigma 85 1.4 lens) you won’t have to separate the background as much.
  3. Wide aperture – so take your lens down to a wide aperture, like 1.4, 1.8, or 2.0. Whatever your widest aperture is for that lens. But be warned, the wider the aperture, the more depth of field you create, and the less of a focal plane you will have. I often times photograph at 2.5 or above and am still able to achieve bokeh. Especially if you have a more telephoto lens.
  4. Lights in the background – to get the pretty bokeh, you need to have light in the background. Without light, you will just get a nice blur (which is sometimes a good thing). In the picture above, the bokeh is created from the sun filtering through the trees. The round circles of light are created because the aperture (the hole in which light is let into your camera) is a circle as well! There are some neat tricks out there to get your aperture to be heart shaped or star shaped. Try googling it!! It’s so fun and creative.

Exercise for bokeh

Let’s give this bokeh thing a shot! I want you to go outside and get some fresh air (that’s always good for you, right?!). Next, take a stuffed animal or a rather large toy (I’m thinking the size of a small baby – toddler). We’re going to practice getting bokeh, as well as getting proper exposure.

Try going out a little closer to sunset. Find some trees, place your subject to wear the sun is on their back (and you are facing the sun). Next, start with a wide open aperture. 1.8, 1.4, 1.2 or whatever the largest aperture you have is. Next change the shutter speed and ISO to get a perfectly exposed image (if you need to, you can meter, take a shot, and check your results on the back of the camera, and then adjust your settings and try again). Do you see any bokeh in your shot? If not, try moving around until you get more light shining through the trees.

If you’re not getting bokeh, are you at least getting blur? Do you like the results? What could you do to achieve a blurry background in most of your images?

You might need one of the following:

  1. Wider aperture (smaller number)
  2. More light shining through trees
  3. The sun needs to be behind your subject

If you’re still not achieving bokeh, the tree coverage might be too thick to let enough light through.

How to isolate your subject or include the background

There will be times as you grow and develop as a photographer that you will want to either isolate your subject from the background, or include the background in the image. So how do you go about doing that? It’s a lot easier than you might think.

Let’s first discuss how you can isolate your subject from the background. We talked a little bit about this in the bokeh lesson.

First things first, in order to isolate your subject from the background, you need to pull your subject away from the background. Check out the diagram below:

The more space you have between the subject and the background, the blurrier the background will be. The lens you choose does have an effect on how far you need to put your subject. Let’s break it down some.

The wider the lens, the more of a distance you need in order to have a really blurry background.

Here are the factors you need to isolate your subject in your images:

  1. A wide aperture
  2. distance from the background to your subject
  3. focal length

If you’re able to get far enough away from the background, I would really suggest you also have a little bit of a closed down aperture (I’m talking still really wide, like 2.5 or something) just to ensure that your subject is in the plane of focus.


Now let’s talk about how to include the environment in your shot.

You don’t necessarily have to have your aperture as closed down as your lens can go (f/16 or higher) to include the background in your shot. It depends on the look you are going for. Do you want it to appear as if the whole image is in focus?

This would come in handy in a landscape shot:

But if you’re just wanting to include the background, enough for it to be noticeable what’s in the background, then you go do an f-stop of f/5-8.

You might want to include the background in your shot if it helps tell a story. Maybe you’re at Disney Land and you want the castle to be a little in focus (but still a little blurry). I would go with an aperture of about f/5 for that. Especially if you’re still pretty far away from it, you’ll be able to tell it’s the Disney Land castle and also have your subjects in focus, but the castle won’t be tack sharp.

You might want to include the background in your shot if it’s pretty landscape. I love taking pictures of my son with pretty landscape behind him. So I usually have my aperture at around f/8 or higher to get the landscape and him in focus. Sometimes it’s nice to blur the landscape out, but it’s also fun to have the background included.


Playing with aperture creatively to get different effects is really fun! As I said earlier, I’m currently writing a blog series about manual mode and I’m also writing a course about manual mode.

If you’d like to receive updates on this course and to also find out when the next blog post is posted about manual mode, please sign up below! I’m also including a FREE Aperture Cheat Sheet when you sign up for my newsletter.

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