This is it! This is what you really need to know, in order to take control of your photo-game!

If you know these three core pillars of photography – you know more than most people out there!

In this post we will cover how shutter speed, aperture and ISO all works together to make the perfect photo. I will not get into way to many details in this post about what the three of them do specifically – but i´ll leave links below, that explain them in depth. They are, like this post, simplified to make it as easy as possible to understand.

Every time we take a photo, we call it taking an exposure. In every camera ever made, there is a sensor (in old cameras there is film, but it works in the same way), being exposed to light. If the sensor is exposed to the right amount of light, the picture, or exposure, turns out the way you want it to. So far, so good?

There are three ways to control the exposure. And yes, you guessed it – those three are; aperture, shutter speed and ISO.

In the table below the first row shows what effect different apertures (f/1,4 -f/32) will have on your photo, the second row shows what effect different shutter speed will have, and the last shows the effects of ISO.

Exposure triangle

The different effects of shutter, ISO and aperture


The lens, attached to the camera, has an opening called aperture. That opening can be adjusted to be big, or small. Big hole lets in lots of light, and small opening lets in less light.

Shutter speed

The amount of time between the curtain in your camera opens, till it shuts. All the light picked up by the sensor in that period of time, will be shown in the final image. If the shutter speed is fast, the curtain open and close fast, and lets little light in. If the shutter is slow, it is left open for longer, and lets more light in.



ISO is how the sensor reacts to the light being let through. A low ISO value, makes the sensor less sensitive to light, and a high value makes the sensor more sensitive. That way we can capture images in low lights, not having to adjust the shutter speed or aperture – if we don´t want to. With high levels if ISO comes grain – and that looks bad. But sometimes it´s better to have some grain in the image, than to have a blurry image.

Exposure triangle

Exposure triangle

Exposure triangle

So let´s get to it!

The three pillars of exposure, are all dependent on each other. Let´s say we found the perfect setting for the shot being at f/8 (aperture), with a shutter speed 1/400 of a second with ISO 400. No matter which one of the settings we choose, we say that once we double, or half one value, we change the exposure by one stop, or f-stop.

So let´s say we change the shutter speed from 1/400 of a second, to 1/800 of a second, to be able to freeze time, and catch a car going in high speed. What we have in fact done, is cutting the amount of light entering the camera in half, because the shutter was only left open for half the time. Given that the settings we started out with gave a perfect exposure, we have now underexposed the shot with one stop. It will look too dark.

In order to fix this, we must bring either the aperture, or the ISO up one stop, to compensate. And for every time we double, or half one value, we change one stop, right? So in order to let more light into the cameras sensor, we can open up the aperture, from f/8, to f/4, or the ISO from ISO 400 to ISO 800.

Just ro recap – first we cut the light in half, by leaving the shutter open for half the duration, and then we brought the light back in, by opening the aperture from f/8 (small opening) – to f/4 (bigger opening) or by rising the ISO to ISO 800. 

The very same of course goes for letting in more light! Let´s say we changed the shutter speed from 1/400 of a second, to 1/200 of a second. Now the curtain in the camera is open for double the amount of time, letting in double the amount of light. That will in turn leave us with a photo that´s one stop to bright, right? So in order to keep the light out, we can make the aperture smaller, by changing it from f/8, to f/16. The size of the hole in the lens will be half as big. We could also change the ISO from ISO 400 to ISO 200, making it half as sensitive to light.

How to find the perfect exposure?

We of course want to get you out of the auto-mode in your camera, and getting familiar with the Manual mode. This is where we have full control over the exposure, and get to get creative! But when learning there is a great thing to start by setting the camera to auto-mode, paying attention to the settings the camera choose for you. Let´s say the camera say Shutter speed 1/400, aperture f/8 and ISO400. Switch to Manual mode, and start playing. Set the shutter speed to 1/1000 of a second, and adjust the aperture until you get the right exposure. Then set the ISO to ISO 100, and see what you have to do, to get back that perfect exposure 🙂

In absolutely no time you will start getting to know your camera, changing things on the go, in supersonic speeds. It will seem weird at first – but it´s the only thing that will help you get comfortable with your camera. Just imagine how much cool images you can get when really knowing your camera inside out!

I hope this was what you were looking for – and that you got the basics down! 🙂 If you have any comments, or questions  – please – feel free to leave them below, or send me an email.

Good luck guys – and happy shooting! See you out there 🙂

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