Weekly Photo tip: What is Aperture? | Pittsburgh Portrait Photographer

Comparing different aperture settingsvpinimageVWhat is aperture? Why is it important? Understanding aperture (“f-stop” like “f/5.6”) is just one of the 3 “legs” of the exposure triangle (more on that in the coming weeks so stay tuned!). Your camera lens has a hole (the shutter) that opens up when you hit that shutter release button. Aperture is how big that hole is. The larger the opening, the shallower the depth of field (aka sharp subject, blurry background). The aperture controls how much light enters the camera and hits the lens. Much like your pupil, which gets bigger in a dark room, “opening up” your aperture lets more light into the camera.

Still with me? Ok hang on we’re going for a ride that may spin your mind a bit. Here we go. The LOWER the number (like f/2.8), the LARGER the opening letting in MORE light. This gives you a SMALLER depth of field. Conversely, HIGHER f-stops (f/22) let in LESS light and give you a LARGER depth of field. I know, you want to punch me right now. Please don’t ask me why that system is like that! But here is a quick summery:

Showing the difference between large and small aperture settingsvpinimageV

 “LARGE” aperture = SMALL f/number = MORE light = SMALL depth of field (DOF)

“SMALL” aperture = LARGE f/number = LESS light = LARGE depth of field (DOF)

Ok go ahead and scream at your monitor, I’ll wait 😉

But at least some of that coincides (small f/ = small DOF)…. ok so what do these f-stop numbers look like? Here is a little diagram for you (image from Wikipedia) The full stops range from about 1.0 up to 64 and beyond.


Knowing which aperture to use for photos can really make a good photo into a great photo. For example, using a large aperture (like around f/4) is great for portraits or details because it blurs out distracting backgrounds and keeps the focus on your subject. Using a smaller aperture (like f/11 and up) works great for landscape shots to make sure you have the whole scene in focus. See the photos at the top for examples of these.

The good news is that if you aren’t ready to try out manual mode just yet, your camera probably has an “aperture priority” mode (Shown as “A” or “Av” on your camera). Putting your camera on this mode lets you select your aperture and then the camera takes over to adjust the rest of the settings to get the proper exposure. Awesome! So…..  how do you practice?

I’m giving you homework 🙂 All you need is your camera and any object to photograph. Go ahead and place that object on a table or the floor, preferably somewhere bright. Set your camera on the smallest f/, focus on your object and snap a photo. Then adjust to the next f/ and try again. Do this up to about f/22 (or as high as your lens lets you). Take a look at all of your photos and notice the depth of field change throughout the images.

examples of different aperture settingsvpinimageV demonstration of aperturevpinimageV

(this was shot at f/16 and I shifted my focus from the front legos onto my son)

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