What is Exposure? Everything You Need to Know [Get Off Auto Mode Series]Hey there! Travel looks a little different right now. Please be sure to follow local restrictions and double-check openings and guidelines for places you visit. And stay safe and wear a mask! Also, his blog post likely contains affiliate links, including Amazon Associates links. If you make a purchase through one of them I may receive a small commission at no extra cost to you.
If you’re looking to get off auto mode and start shooting in manual mode, then one of the main things you’re going to need to understand is exposure. Although I gave a pretty decent overview of this in my post about how to shoot in manual mode, I wanted to take an even deeper dive here because it’s just so important. So let’s dive in!
This post is a part of the Get Off Auto Mode series! Check out the rest of the posts in the series here:
- EVERYTHING YOU NEED TO KNOW ABOUT SHOOTING IN MANUAL MODE
- UNDERSTANDING APERTURE: WHAT YOU NEED TO KNOW
- UNDERSTANDING SHUTTER SPEED: WHAT YOU NEED TO KNOW
- UNDERSTANDING ISO: WHAT YOU NEED TO KNOW
What is Exposure?
Exposure is essentially just how bright or dark your photo is.
It’s controlled by how much light is let into your camera when you take the photo, which is controlled by three different things: aperture, shutter speed, and ISO, which we’ll get into a little bit later on in this post.
What you’re aiming for when you shoot in manual mode is perfect exposure. Basically, you want to have your photo be the right amount of brightness so that it looks like it did in real life.
Here’s an example of a photo with perfect exposure:
When a photo is over-exposed, that means it’s too bright, and will look like this:
And when a photo is under-exposed, that means it’s too dark, and will look like this:
Why Understand Exposure?
It’s important to understand exposure if you want to shoot in manual mode, but also because no matter what mode you’re shooting in, exposure effects so much of your photo. It doesn’t just control how light or dark your photo is, but it also effects the depth of field (how much is in focus), movement, and noise.
If you want creative control over your photos and to get off auto mode, then you need to understand exposure!
There are 3 different settings which control the exposure of your photos: aperture, shutter speed, and ISO.
Aperture is the hole the light goes through, shutter speed is how long your camera’s shutter is open, and ISO is how sensitive your camera is to light. We’ll take a deeper dive into each of these settings now.
Aperture is the hole in your camera that lets light in, which then hits your sensor which records the photo.
You control the aperture with a dial on your camera, and choose the aperture setting based on how much light you want to let into your camera, as well as how much you want in focus.
Aperture is measured in F-stops, which range from 1.2 to 22. The smaller the number, the bigger the hole is (and the more light is let in). The bigger the number, the smaller the hole is (and the less light is let in).
So if you have a bigger number, like 22, you’ll have a smaller hole and a darker photo.
And if you have a smaller number, like 1.2, you’ll have a bigger hole and a brighter photo.
The other thing that aperture controls is the depth of field of your photo, or how much is in focus.
When you use a smaller f-stop number, less of your image is in focus, meaning that you can create blurry backgrounds like this:
When you use a bigger f-stop number, more of your image is in focus, meaning that you can have sharp, crisp photos like this:
So if you want creamy backgrounds for a portrait, then you’ll want to choose a smaller f-stop, like 1.2, but if you want to take a landscape photo where everything is in focus, you’ll want to choose a bigger f-stop, like 22.
For a deep-dive into exactly how aperture works, be sure to look out for the post in this series all about understanding aperture!
The next setting that controls the exposure of your photos is shutter speed.
Shutter speed is how long the shutter of your camera remains open, letting light in.
Shutter speed is measured in seconds and fractions of seconds, all the way from 30 seconds (or longer) to 1/28000 seconds (or shorter).
Depending on how long your shutter is open, more or less light is let into the camera because it has more or less time to get there.
The longer your shutter is open (the bigger the number), the more light is let in, resulting in a brighter photo.
The shorter your shutter is open (the smaller the number), the less light is let in, resulting in a darker photo.
Just remember that when you get down to fractions, the bigger the number on the bottom the smaller the number actually is! So 1/4 is a bigger number (and therefore a longer amount of time) than 1/8.
Of course, you also need to take into account aperture when you’re setting your shutter speed, because depending on how big the hole you’re letting light into is, the faster or shorter your shutter speed needs to be in order to get the right amount of light for perfect exposure.
The bigger your aperture hole is, the more light can be let in quickly, so you only need a short amount of time in order to let enough light in for perfect exposure. So you only need a short shutter speed.
The smaller your aperture hole is, though, the less light can get in at one time, so you’ll need a longer amount of time in order to let enough light in for perfect exposure. So in this case you’ll want to use a longer shutter speed.
In addition to exposure, shutter speed also controls how much movement is captured by the camera.
If your shutter is open for a super short amount of time, then movement will be frozen, like this:
If your shutter is open for a longer amount of time, though, then movement begins to blur, like this:
This is a great thing to have control over, because it allows for so many different creative opportunities. You can either freeze a moment in time or do something really cool, like blur the water of a waterfall for a lovely effect like this:
For a deep-dive into exactly how shutter speed works, be sure to look out for the post in this series all about understanding shutter speed!
The final component that controls your image’s exposure is ISO. ISO is basically just how sensitive your camera is to light, and it’s measured in increments of 100.
The smaller the number is, the less sensitive your camera is to light, and the darker your image is.
The bigger the number is, the more sensitive your camera is to light, and the brighter your image is.
ISO is separate from shutter speed and aperture, so no matter what you set for those two things, the image will become brighter or darker based on the number ISO setting you choose no matter what.
In addition to exposure, ISO also controls noise.
Noise is when your image is grainy, like this:
The more sensitive your camera is to light (aka the higher your ISO), the more likely it is that you’ll get noise in your photo. So in general, you want to keep your ISO as low as possible to avoid this, and make compensations with your aperture and shutter speed to make your image brighter wherever possible.
For a deep-dive into exactly how ISO works, be sure to look out for the post in this series all about understanding ISO!
The Exposure Triangle
The three components which control exposure (aperture, shutter speed, and ISO), all come together to create something called the exposure triangle.
In the exposure triangle, each side of the triangle represents a different setting. So one side is aperture, one side is shutter speed, and one side is ISO.
As you move along each side of the triangle, your image becomes either darker or brighter.
3 sides represent 3 different components
As you move along each side, the image becomes brighter or darker. Here’s a really great animation which explains exactly how that works!
Finally, if you’re shooting in anything other than manual mode (such as aperture or shutter priority mode), then you’re going to want to pay attention to a little thing called exposure compensation.
Exposure compensation is a little dial which you can use to alter the exposure which is set automatically by your camera. So if it reads things wrong and it’s giving you a setting that’s too bright or too dark, you can scroll up or down in order to change the settings.
And there you have it – everything you need to know about exposure! Hopefully this answers the question: what is exposure, as well as any other questions about exposure that you might have had. Now grab your camera and start practicing!
Read some more travel photography posts from me:
- Travel Photography Tips for Beginners: The Ultimate Guide to Travel Photography
- 7 Travel Photography Myths + Why They’re Not True
- Composition and Lighting: 2 Secrets to Great Travel Photos
- 14 Travel Photography Mistakes & How to Fix Them
- Travel Photography Essentials: The Top 11 Lenses & Accessories You Should Never Leave Home Without
- How to Choose the Best Camera for Travel Photography