What Is Aperture? Quick Lesson

What’s this thing called aperture?

In short, aperture is what controls how much light gets into the camera. In addition to controlling how much light gets into the camera, aperture also affects your depth of field.

We’ll get into depth of field in another quick lesson, but what this is referring to is how blurry is the background of your photo. The lower the aperture the more blurry the background of your photo and more attention you need to pay to focus.

The lower the aperture on your lens the better. Hold on… you just said I’d need to pay more attention to focus at a lower aperture.

True, but a lower aperture number actually lets more light in. Yes, it’s counter-intuitive but it doesn’t take long to get used to.  By the way, aperture is expressed in the form of “f/” then the number. So a f/2.8 lens would let more light in than a f/4 lens. There are fixed aperture lenses and variable aperture lenses. Fixed aperture lenses can stay at the lowest aperture they are capable of at any focal length. Generally these lenses cost more. Variable aperture lenses use a higher aperture as you increase the focal length. A popular variable aperture is f/3.5 – 5.6. So a f/3.5 to 5.6 would be f/3.5 at it’s shortest (widest) focal length and f/5.6 at it’s longest (most zoomed in) focal length. Keep in mind you can set the aperture higher if you need to, but these numbers represent the lowest available aperture for that lens. Wait.. what is focal length? Think of focal length as zoom. How wide of a view are you getting vs how zoomed in are you. The lower the focal length the wider the view and the higher the focal length the more zoomed in (narrower) the view.

Why is letting more light in important?

To explain this best we also need to introduce ISO and shutter speed. In short ISO is how sensitive your camera is to the light it sees and shutter speed is how long your shutter stays opened.

If you have less light you need a higher ISO. Ok, so? Well the higher ISO you use the higher chance you have of your photos and videos being grainy (fuzz). With today’s cameras this isn’t as much of an issue, especially with higher end gear, but as a general rule of thumb the lower the ISO the better the quality of the photo or video.

So why does shutter speed matter?

In photography shutter speed matters because the longer your shutter is open, the more chance you have of the photo being motion blurred. Even the slightest undetectable movement, to you, can ruin what would have been a great photo. If you’re taking a photo of subjects or objects that aren’t moving and you have your camera on a tripod, you can use lower shutter speeds without as much risk of motion blur. If you are moving or your subjects are moving, you’ll want to use a higher shutter speed. The more movement the faster the shutter needs to be. How this relates to aperture is the less light you’re letting into the camera (remember… aperture controls how much light you let in), the longer you’ll need to keep the shutter open. If you let more light into the camera, with a lower aperture number, you can use a higher shutter speed.

What about videography?

In videography the rule of thumb is to have your shutter speed set to double your FPS (frames per second).  This is known as the 180-degree rule. Having your shutter speed too low can cause the motion to be blurred. Setting your shutter speed too high can cause your video to look jerky, or choppy. So an example is, if you’re recording at 24p (24 frames per second) you’ll want your shutter speed to be at 50 or 1/50 of a second. Tying back to aperture, if your aperture is too low and you do not have a lot of light, your video will be too dark unless you set your ISO high, but if you set your ISO too high, your video could be grainy.

Ok, but I’m not recording in the dark.

Well, to get great quality photos and videos cameras require a lot of light. This is either in the form of adding light to the scene with lighting equipment, and/or in the form of a camera and lens that lets a lot of the available, also known as ambient, light in.  If you’ve ever seen a film set you know that they use a lot of lighting equipment. This is one of the reasons why.

So what does all of this really mean?

We could go into a lot more detail, but the point of the Quick Lessons are to give you a basic understanding and brief introduction to the topic. This will by no means make you an expert photographer or videographer, but hopefully you’ll leave here knowing a little more than you did before.

Our recommendation, if you’re buying gear, buy the camera/lens with the lowest aperture you can afford. Obviously there are other factors to consider, but our focus for this post aperture.

If you’ve already bought your gear, when you’re in a darker setting use a lower aperture for higher quality photos and video. Keep in mind though this will affect your depth of field (how blurry the background of the photo is). You also need to pay more attention to focus at a lower aperture. If your subject moves just a matter of inches they could be out of focus. If you’re still reading this either you’re really interested in our blog, or you’re likely a beginner. If you’re a beginner, we suggest you use auto-focus.

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