Have you ever taken a photo of something (or someone) and you just didn’t like something about it, but you didn’t know how to fix it? Understanding exposure triangle might help you with that.
Exposure triangle is the foundation of photography. Once you get how the exposure triangle works, you will be able to get great exposure and creative control of your photos. It’s the most basic concept in photography.
Exposure is not just brightness and darkness of images, we can also have blurry or noisy images or nice and crisp, or even images with a lot of things in focus or with just one thing in focus.
What is exposure triangle made of?
- Aperture
- Shutter
- ISO
It’s actually an intersection of these 3 things that an images exposure is worked out at.
The important thing is that a change of one those elements directly affect the other two, so you can never isolate just one of them alone, but always have to have the other two in mind.
- Aperture is inside your camera lens and it lets more light in or less light in. Its values are marked with numbers (f/22, f/16, f/11, f/8…) and the smaller the number is the larger the opening gets, and the larger the number is the smaller the opening gets (it sounds backwards, but I will explain that).
- Shutter speed can be set to very fast speed or you can slow it down. It kind of does the same thing as the aperture – lets the light in. So really fast shutter doesn’t let very much light in and the slow shutter lets more light in (I hope you get it). So since the both things kind of do the same thing, they have to be balanced. Basically, if one of those two things lets a lot of light in, the other one need to be restrict so we don’t let too much light.
- ISO controls sensitivity of our camera to light. It’s also marked with numbers (100, 200…6400, 12800) and the smaller the number is the less sensitive our camera is to light, but the higher number we choose the more noise we get in photos. So, we have to adjust our ISO to the light but also to balance it aperture and shutter too.
The judge of that would be meter which is built in almost every modern camera. If you set aperture wideness and the ISO, the meter figures out how fast the shutter speed should be or if you set the shutter speed and the ISO the meter can figure out the ideal wideness of aperture.
If you are wondering which one you should start with, it depends on what kind of photographer you are. For instance, if you are a portrait photographer you will probably want to set the aperture first because it controls how much of an image is in focus, but if you are, let’s say sports photographer and you deal with motion, you will want to set the shutter first because it controls motion (it either freezes or shows motion).
Aperture
Aperture shows how long you let light in.
Aperture controls depth of field.
For portrait you have to set your aperture really wide (f/1.4) and be really careful with focus. That’s how you get sharp portrait and the background will fall out of focus. But what happens if you don’t have f/1.4 aperture value, you might ask.
If you are stuck at f/5.6 or f/2.8 you can still get really sharp photo, because it’s not only the aperture that determents the depth of field, but the size of your lens, the focal length and the distance of your subject (how close you are). For out-of-focus background you shouldn’t shoot with wide angle lens because it would have everything in focus. Instead, you should shoot with 300mm or 200mm lens (or even smaller). Also, the important thing is the distance of your subject.
The closer you get the more out-of-focus your background is going to be and the further away you get the more things are going to be in focus. So if you want to get shallow depth of field you should use the longest lens you can get and get as close as you can with the widest aperture you have, and you will get the perfect shoot.
Aperture is written as f/number. You might wonder what does the f mean and why is it that the smaller number means a bigger hole and the bigger number means the smaller hole. Well, it is simple math and I’ll try to explain it to you in the simplest way possible.
F is actually symbol for focal length and let’s say we have focal length of 100mm (f=100) and the aperture value of 2 (I’m making up the numbers). When you write it down as a simple math operation you get (f) 100/2=50, so the opening in our aperture is 50mm wide.
Or if our focal length is 300mm and aperture value is still 2 then opening aperture is 150mm wide (300/2=150)
If you have bigger aperture value, let’s say 5 (f/5), you will get smaller opening in aperture, simply because you divide focal length with bigger number (300/5=60).
Shutter speed
Shutter speed shows how large of an opening you let light through.
Shutter opens and closes using the shutter speed to control how much light comes into the camera. You can have really fast shutter speed like 2000th or 4000th of a second that doesn’t let much light and very slow shutter speed like a half a second or 15th of a second that lets in a lot of light. Shutter also controls the duration of the light and it controls motion that can be of something moving or of us moving a camera.
- When you are shooting something that is moving, with slow shutter you get the motion blurred, but with fast shutter you get the frozen motion.
- When you have the camera in your hand and not on tripod, the camera moves a little. Depending on the lens you use your shutter speed needs to be set appropriately or you’re going to have more motion. This is very important when it comes to shooting a video.If you have a long lens, the shutter speed needs to be faster than if you have a short lens. In fact, there is a rule that helps you understand how fast your shutter speed needs to be: Your shutter speed needs to be at least as fast as the length of your lens (or faster).
For instance: If you have a 21mm lens your shutter needs to be at least 30th of a second or faster (because there is no 21th of a second) or if you have 135mm lens, your shutter speed needs to be about 200th of a second or faster. Longer your lens is the faster the shutter speed needs to be.
ISO
ISO shows how sensitive your camera is to light.
The higher the ISO value is the less light you will need to take a photo. Each time you double the ISO value you will need half as much light, but the higher your ISO is, the more noise your photos will have. So, you should keep your ISO value as low as possible because you don’t want noise in your images, if you don’t have to.
In low light, I would rather set my ISO higher and get noisy images, than set my ISO lower (which means my shooter speed needs to be lower) and get blurry images that I can’t use.
To find out what is your cameras maximum acceptable ISO value you can shoot series of images in low light increasing ISO with each shot. When you look at the photos at full resolution on your computer, you will know.
Conclusion
Balancing out all 3 things that make the exposure triangle gives us the perfect light, sharpness and focus and that juggling takes a lot of practice.
As long as you are using exposure triangle correctly you can’t get a bad photo and you’ll still be able to make some adjustments in order to give your photo a new life.
Once again, adjust your ISO to the light, aperture to what you want in focus, let the meter set your shutter (or set the shutter first and let the meter set the aperture) and, voilà!
- Try to use the lowest ISO possible.
- For faster shutter speed use wider apertures.
- To prevent motion blur, shutter speed should be at minimum.
*Keep in mind that you will have to experiment as you go and adjust your settings to the light that is constantly changing.
I hope you’ll enjoy playing with it until you get the perfect shot!
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