Lens Aperture

Aperture Priority Mode

Aperture Priority Mode or A/Av lets you select the aperture on your lens.  In Aperture Priority mode, you tell the camera how large you want the aperture to be, and the camera will set the shutter speed & ISO accordingly. AV, mode, by the way, stands for Aperture Value.

Aperture determines two things- 1. How much light is coming into your camera thru the lens and, 2. How much depth-of-field you want in your photo- aka background blur. The lower the aperture number, the less depth-of-field you have, meaning the more blurry your non-focused areas will be. The greater the aperture number the more depth of field you have, so more of the photo will be in focus, even the things that you weren’t intending to focus on. 

You can make the aperture larger to let in more light, or smaller to let in less light. It works just like the pupil in your eye. The pupil gets smaller in bright situations and larger in dark settings

Some real-life examples- 

If taking a portrait of someone, by having a low aperture we can put the focus on our subject and have a nice out of focus background, letting the subject “pop” off the screen.  This is also great for hiding clutter. 

If you are shooting a faraway landscape photo you may want to have the whole landscape in focus so you would choose a higher aperture number. 

landscape - large aperture


I want you to dial in the A or AV mode on your main camera dial. This will put your camera in Aperture Priority mode. Once your camera is in AV mode, you need to find the dial that adjusts the aperture. If you need help, check with your camera manual. 

Take a picture outside on aperture f/7.1. Look at the photo on your computer. Describe your focal point, note how much of the photo is in focus and how much is blurred.  Do this exercise again with a different aperture and note the differences between the two photos. 

Key takeaway-

Larger apertures let in a lot of light and focus on a small part of the photo. Smaller apertures let in smaller amounts of light but focus on a much larger part of the photo. For more on aperture be sure to check out Understanding Aperture

The real key to amazing photos is to practice, practice and practice some more.  Get out there, take photos of everything, experiment with all the different modes and different settings and then study the results.  Check out our Capture Your Adventures Resource Library for downloadable PDF’s to help you along your photography journey.