To put it simply, aperture controls the opening of the lens. The aperture number determines how wide your lens opens when you take a photo and how much light is let in. Aperture is measured using the term f-stop; typically seen as f/1.4, f/2.8, and so on. The number range and results vary for each type of lens. An example of a lens with a higher aperture would be the Canon EF 50mm f/1.4, with the the Sigma 70-300mm f/4-5.6 having a low aperture.
The aperture setting is one of the most confusing of them all to a large majority of DSLR camera users. Lower apertures let more light into the lens, ideal for shooting indoors or at night. Higher apertures let less light into the lens, ideal for shooting in ample lit conditions or outdoors in natural sunlight. As backwards as this all sounds, it is what it is and practice makes perfect or decent, or whatever tickles your fancy. Although, a great deal of masterpieces happen on accident!
- Low f-stop number (f/1.4) = more light and more background blur
- High f-stop number (f/16) = less light and less background blur
Aside from lighting, aperture is also used to create depth of field, also known as background blur. When you have a small numbered aperture such as f/1.8, the subject will be in focus and the background will be very blurry. When you have a higher aperture such as f/16, everything in the photo will be in focus rather than the background being blurred out.
As you can see in the examples, the higher the aperture setting, the more clarity is shown in the background of the image. You’ll also notice that the higher the number gets the darker or less exposed the image becomes. The photos below were shot in manual, but if aperture is important to your particular shot, you’ll shoot in aperture priority (Av), meaning that the aperture setting will stay in place even if you adjust any other settings on the camera. When shooting in manual (M), the exposure of the image depends on aperture, shutter speed, and iso, but that’s a lesson for an upcoming post.
So how do you change the aperture setting? Well it varies per camera model so you may want to cozy up with your manual. Some photography backdrops can also affect this. In this pictorial, I’m using a Canon 60D. As you can see in this image, the camera is in manual mode and the aperture is listed on the screen as 1.8 next to the letter F.
To change the aperture setting on the Canon 60D, When in manual mode turn the quick control dial on the back of the camera. When in aperture priority mode, turn the main dial near the shutter button. These dials will change the f-stop number either higher or lower depending on which way you turn them. Turning left or counter-clockwise will open the lens, turning right or clockwise will close the lens.
Play around with your settings for a while to see if you can figure out how to better control your aperture settings to improve your photos. It will take some time to catch on, but it will make a world of a difference in your photos.