Camera Settings Explained - ISO, Aperture and Shutter Speed. By Oliver Milburn free stuff

Having been asked a few questions recently, I thought I’d take a moment to explain how to use the three fundamental settings inside of every camera. If your digital camera has a Manual setting (often represented with an M) then you can control each of these three settings individually to achieve a desired exposure your specific camera will allow for.

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I am quickly going to explain the basic principles of the three settings and how they affect your real life situations.


In my infographic (above), the circle represents light. The middle most point is the lightest situation (such as a tennis match) and the sides are the darkest (like an indoor concert). In low light situations you would naturally be looking to increase the amount of light to make the image closer to representing real life. Before using a flash gun, there are three ways to increase the amount of light your camera’s sensor can see.

Shutter Speed (S) – Slow it down and open the Shutter for longer to allow more Light in to the Camera

Aperture (A) – ‘f number’ is another word for Apperture. The lower the ‘f number’ the more Light goes in to the Camera

ISO (ISO) – Increase the ISO. This will allow the Sensor to become more sensitive to Light

The two top settings (S and A) are actually modes on a lot of Camera’s. They give you manual (M) operation of each setting and make the camera control the rest.

Using S, A and ISO together

Each of the three settings come together to create an exposure. You can not turn one of them off. They make every image.

Rather than explaining with words, look at the infographic above and the three different scenarios I have featured. I’ll explain in a bit more detail below because I’ve been asked a few questions recently and this should help answer them.


You should be using a tripod. The good news is that the shutter speed is on your side here. This is because the amount of time you have to take the shot is dictated by the movement in the scene. In this situation below, the only movement in the scene was the clouds passing overhead and the projections being refreshed on to the Parliament buildings (approx 7 seconds each).

Nightscape by Oliver Milburn

Generally, to avoid noise (grain) in your images, turn the ISO right down very low, the same as you would in the bright snow or on a beach in Florida. Only increase it if you’re finding the image is under exposed. The Aperture can be set to anything here and can act as a sort of counterbalance to your other two settings, however you may find your images sharper at a higher f number such as f8. Use the built in timer to avoid any movement and you will get a clean, noise free image with a controlled amount of movement and depth.


At a concert you would be looking to capture a sharp image of the band without adding too much distraction from the main subject. Your shutter speed will have to be faster, something like 1/100 of a second +, and pick your moment carefully to avoid any unnecessary movement. The ISO will be set as high as your camera will allow before it gets noisy. You will most likely be using a zoom lens so zoom in quite a way to encourage a blurred background. Most compact cameras get very noisy at anything above 400 ISO. So just be careful here. The Aperture will need to be set to a low f number. The lower you can go, the more light will come in to the camera.

Tennis Match

Tennis is an outdoor sport which means it relies on natural light. Your ISO can be set higher than you would expect here because you will be fighting against quite a lot of athletic movement and you should avoid under exposing. Shutter should be quick, something like 1/250 of a second or faster if your camera will allow. The f number you can keep quite low, but remember the lower you go, the shallower depth of field you will see. So you may only have a few metres in focus and blur the backgrounds right out, or miss the subject completely due to bad focusing. Use spot focus to avoid this and set the AE/AF Lock button (if you have one) to lock out Automatic Focus. Keep it held down and be ready to press the shutter when the time is right.

I hope some of this helps.


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