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  • Writer's pictureLele Bonz

Camera basics: Manual Exposure

Updated: Feb 21, 2022

Welcome back!

Hi, friend! I hope you're doing well.

Today we're diving a bit into the first steps on how to finally have full control of your camera. It's time to learn manual mode! I know it sounds scary, but it is so much easier than you think. Let me explain it in the easiest way possible.

Alright, so you have your camera, but you have always used it in automatic. No judgment, we all started there. However, you can't stop wondering how much better your photos would be if you stopped the camera from making all the decisions. And, let me tell you, it changes A LOT! In fact, for how smart the software inside your camera can be, you are the one who is actually there deciding what and how to photograph. It's a bit hard to be creative if a computer is making all the technical decisions.

So, let's actually start learning how to use your camera in manual mode. Since there's a bit of things to talk about, today we are focusing only on exposure. We will move onto motion and depth of field later.

Switch your camera wheel from A (automatic) to M (manual) , and let's begin.

Alright, you have to know that there are three main fundamentals of manual mode (four if you consider white balance, but let's skip that for now).

These components are F-Stop, Shutter Speed, and ISO. Let's learn what they are, and how do they relate to exposure.


F-Stop (or Aperture)

F-stop is the term used to denote aperture measurements in your camera. I know that it means nothing to you but hold on. In your camera, you will see it on the screen written down as F- "number". It tremendously impacts exposure and depth of field, which we will talk about another day.

Every camera is different, so you might want to look up online how to adjust your F-stop. There is usually a wheel on your camera that lets you regulate that.

What is F-stop, or aperture? In simple words, it means how much the lens is open. If it's very open, more light will come in. If it's not open, not a lot of light will come in. I know it still might not make sense, but keep it in mind.

Let's do a little exercise. Close your fist and make the smallest hole possible so that you can barely see through it. Now, look through it as if it were a viewfinder. It's kind of dark, isn't it?

Alright, now open your fist and make the biggest circle that you can with your fingers. If you look through it, there's a lot much more light than before, right?

Go back and forth, gradually, from the smallest hole to the biggest circle you can do with your hand. The bigger the circle is, the more light comes in.

I know this metaphor is not the best, but it gives you a good idea of how this works. Your lens works in the same exact way. Therefore, if your lens is more "open", you will let more light in. If it's more "closed", there will be less light.

The smaller number you see on your F-stop, such as F 1.8, is equivalent to the most "open" you can make your lens. So, if you set your aperture to F22, you will have way less light than if you set it at F4.

That's all there is to it!

Bigger number = less light.

Smaller number=more light

For future reference, know that a smaller aperture also means a shallow depth of field. Do not wrap your mind on it too much for now.


Shutter Speed

The second component that influences exposure is shutter speed. Shutter speed makes more sense for Reflex or Film cameras because it's exactly what it is: how fast your camera's shutter closes. Mirrorless cameras do not have a physical shutter, but it works in the same way, only digitally.

What does it mean? Well, when you take a picture, there is a little shutter in front of your sensor that will open and close to take in the image. The shutter speed is how long your shutter will be open for.

Shutter speed affects both exposure and motion in your pictures. However, let's just focus on one for the moment.

How does this relate to exposure?

Let's re-try using the metaphor we used before. Make a fist with your hands. Now, try to open your fist and close it as fast as you can in front of a light while looking through it.

You could not see much, could you?

Now, let's re do it, but do it really slowly.

Now you can see much more of the light.

The same thing happens with your camera. With a fast shutter speed, your sensor has a very small time to gather the light around it. Therefore, with a fast shutter speed (which is a bigger number on the bottom of the fraction), you will not be able to have a lot of light in your image. On the other hand, with a slow shutter speed, your camera will have so much more time to gather as much light as it can.

This is why people who shoot night photography leave an extra long shutter speed, even up to 30 seconds. In this way, the camera has all the time it needs to gather all the light around it. In fact, stars emit a little of dim light, and leaving your shutter open for that long gives your camera enough time to catch it.

This is how they capture images as beautiful as this:

(Of course, they need a tripod to be able to have focus in their image, or everything will be extremely blurry. Check out this post to learn more about this).

How do you see shutter speed on your camera?

On your monitor, next to the F-stop, you should be able to see a number, which is usually a fraction. That's the shutter speed, and it's quantified in seconds. So, if you see 1/4, you are taking pictures at one quarter of a second. If you see 1/200 shutter speed, it means that your shutter is closing at a speed of 1/200 of a second.

If you expose for a long time, such as for many seconds, you will see only a number instead of a fraction. So, if you set your shutter speed at 4, it means that it will stay open for 4 whole seconds.

You should also know that shutter speed also impacts motion in your pictures. For right now, just remember that a faster shutter speed not only lets in less light, but it also freezes motion. A slower shutter speed will let in more light, but register movement more slowly, resulting in blurry pictures (if you want to learn more about this concept, you should check out this blog post about motion).

Let's recap:

A fast shutter speed freezes the image, but has less light.

A slow shutter speed can be more blurry, but has more light.

The higher the number in the denominator is, faster the shutter speed is and vice-versa.



We're almost done, there's just one more!

ISO is the light sensitivity of your camera. In simpler terms, is the capability of your camera to add light digitally to your image. So, the higher the ISO is, the more light your camera will add to your image.

And you might ask, then why do we worry so much about the other two if the camera can do it by itself? Well, here's the catch.

A bigger ISO equals to less quality. Well, it depends by the quality of your cameras, since a most expensive one will be able to handle a higher ISO without missing information.

However, as a general rule, your photo will start showing more noise if your ISO is high. Noise is shown by a picture being grainy. While this is an effect that many people enjoy, you want to do it in post. In this way, you will have the best quality image right out of your camera, which gives you more freedom to do whatever you want afterwards.

This is an example of a very high ISO, resulting in noise:

As a rule of thumb, you never want you ISO higher than 800, unless you have a really nice camera that works in low-light conditions. The lower you can keep your ISO, the best your image will be.


Wrapping up!

Alright, now you know the three components of the exposure triangle.

Why is it called that?

Because you should use these three settings to achieve your desired level of exposure in your images. You should first set aperture and shutter speed, and then use ISO as a last resort.

However, as you know, the shutter speed and aperture also control other variables, such as how fast you freeze the image or the depth of field. So, if you want to catch an action that is really fast, you want a fast shutter speed, which will result in lower light. This is when you might want to use ISO if you cannot add any artificial lighting or a flash to your image. While it's not a crime to use ISO, you want to try to keep it as low as possible to try to preserve the quality of your images.

How can you check if exposure is proper? Or, simply put, how do you know if you have enough light?

There is a little exposure meter on your camera monitor that will tell you exactly that. When it says 0, it means that your photo has the perfect amount of light. If it's over 0, there might be a little too much. If it's negative, you might want to adjust your settings to let a bit more light in. However, this is not absolute, and you can always decide to overexpose or underexpose as you wish.

Here's the meter:


And, that's a wrap!

Now you know everything you need to starting to control your exposure in manual mode.

Do you have any questions? Was this helpful?

Let me know in the comments!

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Hsiao Wei Lin
Hsiao Wei Lin
Feb 13, 2022

Hi Lele, I like your detailed explanation, it's really helpful! Can you teach us how to take good photos with phones?

Lele Bonz
Lele Bonz
Mar 01, 2022
Replying to

Hey, sorry for the wait, here it is!

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