One of the main things I wanted to learn when I first started snapping photos was how to make everything but my subject look blurry.

I thought if ‘I’ could do that, then my pictures would be so professional looking!!

Once I switched to manual mode, I learned quickly that if I shot a subject ‘wide open’ I could get that look I was going for. However, I also realized that only shooting wide open isn’t appropriate for every shooting scenario. Sometimes it’s kind of important to get more than just a small amount of your subject in focus! It all depends on what your vision is and what it is you are trying to achieve. For that reason alone, I highly recommend that if you’re not shooting in manual mode that you switch to manual the next time you pick up your camera in order to maintain more control. Just do it! You’ll thank me later.

Aperture:

Let’s talk about how the aperture you choose will dictate how much is in focus in your photo.In other words, how your aperture choice affects your depth of field (DOF).

But first what is DOF? Depth of Field is the distance in front of and behind your focal point that is sharp or in other words, in focus. This is also referred to as shallow depth of field (shooting wide open; large aperture, ex. f/1.8) or deep depth of field (shooting closed down; small aperture, ex. f/22). There is a fantastic DOF calculator app called Digital DoF by Indie Film Lab. I used to use this quite a lot when I was first learning how to shoot manually. What it does is allows you to input your camera type, focal length, and your aperture and then how far you are from your subject. It then tells you how many inches or feet will be in focus in front of and behind your subject. From there you decide how far away or how close you need to be from your subject to achieve the desired plane of focus. This is especially handy when shooting large groups of people.

Definitions:

Next, I want to discuss common photography lingo used to describe aperture as it can be confusing.

  • Aperture is the term used for how much light is let in or not let in to your camera sensor. The common word for aperture is f-stop. Apertures will range from f/1.2 to f/22, depending on your lens (and some go even larger than f/1.2).
  • Wide open (or a large aperture like f/1.8, remember the hole in the lens is big) means that there is a lot of light being let into your camera; wide open gets you that ‘shallow’ depth of field.
  • Closed down (or at a smaller aperture like f/22) is going to let the smallest amount of light into your camera, also referred to as a deep depth of field (lets you get more of your photo in focus).

So what does all this really mean? I think it’s easiest to show the affect of shooting wide open and shooting closed down through picture examples.

Visual Examples:

These photos were taken at the same distance from my subject.  For each image I focused on the front of the pink sticky.  The back of my camera is exactly 22.5″ from the front of the pink sticky and the wall in the background by the lamp is exactly 28.5″ from the front of the pink sticky. However, with each click of the shutter, I changed my aperture (and ISO and shutter speed to get proper exposure).

how aperture affects depth of field

how aperture affects dof

how your aperture choice affects whats in focus

As you can see, the larger aperture has the least amount of what’s in focus in the frame while the smaller aperture has more in focus within the frame. For a better side-by-side comparison, here are the f/1.4 and f/22.

choosing your aperture and making a blurry background tutorial

And if it helps, this little diagram shows where your focal plane will be depending on your aperture.

focal plane difference with small and large aperture

Distance and Lens Choice:

Changing your aperture is only one way to affect your depth of field.

Here are some examples of that. All of these were taken at f/2.8, on a tripod, and with the focal point on the pink sticky. As you can see, the further away I move from my subject, the more that is in focus.  Also, the wider lens I use, the more that is in focus. You can see that by moving in closer just a small amount, the foreground as well as the background begin to fall out of focus.

photo examples of how your lens and distance from subject affect depth of field

Being creative doesn’t just mean being creative in what you shoot, but it’s also about how you choose your settings in camera in order to attain your vision.

If you’re new to photography and want to learn more about how to use your camera be sure to check out two fabulous workshops First Steps with a dSLR and Mastering Manual Exposure. Both of these will be a great way to learn your camera.