In traditional photography, the term ‘Exposure Triangle’ is thrown around quite a lot. It is said to be key to capturing high-quality images that are well-exposed.
But what exactly is the Exposure Triangle, and does it even matter in smartphone photography?
ISO refers to the camera’s image sensor’s sensitivity to light. A low number means the sensor is less sensitive to light. A higher number means the camera will be more sensitive to light.
In other words, if you’re shooting in bright light conditions, you’ll have to bring your ISO down in order to avoid overexposing your shots. But if you’re shooting in low lighting conditions, your ISO will need to be dialed up, so the image can be brighter.
ISO that is set too high will result in photos with digital noise.
Shutter speed is expressed in seconds and it refers to how fast the shutter opens and closes. The longer it stays open, the more light gets to the camera.
The shorter it stays open; the less light reaches the camera. Therefore, if you shoot with a slow shutter speed like 1s (one second), your picture will come out brighter than if you shot with a fast shutter speed like 1/3000s (one three-thousandth of a second).
A shutter speed that is too slow may introduce blur to your images.
Aperture is a measure of how closed or open the hole where light enters the camera is. This measure is expressed in f-stops. The lower the f-stop number, the wider the opening, and therefore, the more light can get it.
The higher the f-number, the less light can come through the hole. Therefore, a picture shot with an f-stop of f/10 will be darker than one shot with f/1.8.
Adjusting the aperture changes the depth-of-field of your shot.
Also read: Aperture: What It Is & How It Works
These three settings on their own can either contribute to a stunning photo or make it really terrible. Therefore, a perfect balance between them needs to be maintained in order to ensure the picture turns out perfectly.
Now, the question is…
How does it all come together?
You cannot change one setting without adjusting one or both of the other two. Exactly what these settings needs to be depends entirely on what you’re photographing, the lighting conditions, and the desired final picture you’re aiming for.
For example, when shooting portraits, most photographers aim to have a shallow depth-of-field in order to get the bokeh effect that comes from having a blurry background and a foreground that’s in focus. Depth-of-field gets shallower the more open the aperture is.
However, this puts your shots at risk of being very overexposed, especially if you’re shooting in bright light. To counter this, you may have to decrease the camera image sensor’s sensitivity to light by bringing down the ISO.
If the picture still seems to be too exposed for your liking, you can also choose to use a faster shutter speed to decrease the amount of light that gets in.
A low ISO means that there’s very little chance of having grainy pictures, and a fast shutter speed guarantees your pictures will be crisp with no motion blur.
All in focus
When doing things like landscape photography, it’s best to have everything in focus than have a shallow depth-of-field. Therefore, your aperture will need to be small, which means setting your camera to a higher f-stop. That, though, makes the image darker, so you’ll have to increase the sensor’s sensitivity to light and bring up the ISO a bit.
Remember that too much ISO will negatively affect the picture by introducing noise, so you may want to use a slower shutter speed.
You’ll have to play around with these settings to find a happy medium where your shots will neither be noisy nor blurry, and the exposure is just how you want it.
If you’re shooting in low lighting, things are a bit different. Obviously, you’d want your aperture open as wide as possible to allow for maximum light.
Sometimes, this alone might not be enough for a well-exposed photo. Increasing the ISO will definitely help in this situation. And if necessary, you may have to use a slow shutter speed.
As useful as it is to use a slow shutter speed to improve the brightness of a photo in poor lighting, the downside is that it can result in blurry photos if the camera is not still.
You can use long exposure in low lighting to create shots like the one below.
How is it different in smartphones?
Firstly, smartphones don’t have mechanical shutters. Rather, they use an electronic system where the sensor is activated for a set period of time.
This doesn’t really create much of a difference in the performance of smartphone shutter speeds versus those of traditional cameras. The greatest difference is the aperture.
Unlike with DSLRs where the aperture can be changed, smartphones have fixed aperture. If your smartphone camera has an aperture of f/2.2, then that is it, it cannot be changed.
So, even though you can manually change the ISO and shutter speed of your smartphone camera, this obviously limits the amount of control you have over the relation of the three settings in the Exposure Triangle.
So then, if the aperture on smartphones is fixed, …
... does the Exposure Triangle matter in smartphone photography?
I definitely think so. A fixed aperture does not negate the impact that aperture has on the quality of the picture or the role it plays in the smartphone Exposure Triangle.
In my opinion, it’s one the most important things to consider when it comes to smartphone cameras because it gives you an indication of the camera’s potential low light capabilities.
For example, a phone with an f-number as low as f/1.5 can allow more light in than one that’s just f/2.4. More light means better performance in low light conditions. Of course, there are other specs that affect a mobile camera’s low lighting capabilities.
Also, starting with the Galaxy S9, Samsung introduced variable aperture to their mobile devices. This means that you can choose between an aperture of f/1.5 and f/2.4 for varying exposures depending on lighting conditions.
Proper exposure is key to what makes a smartphone photo look great. Even though aperture may be limited on smartphones, understanding the Exposure Triangle and how it works will make a difference in the quality of your photos.
This is especially true when it comes to shooting in Manual mode because when adjusting the settings, it's best you know what you're doing. Once you get the hang of it, you'll immediately realise the benefits of shooting manually.
It may take some getting used to. The most important thing is that you keep practicing until you get it right.