The Three Most Important Settings On Your Camera

The Three Basic Principles of Photography

Last week I was planning upcoming content for my blog, and asked a lot of other parents what they would like to know about when it comes to taking photographs of their children. There were a lot of topics that came up (some that came up frequently), but one thing that struck me is that it would be helpful to have some posts on different camera settings that you can refer back to when reading other posts. So today’s post focusses on the three most important settings on your camera. Next week I’ll dive into all the other topics that you want to hear about!

Before we get started, a little disclaimer. This post gives a very basic overview of the three most important camera settings – it’s by no means an exhaustive guide to using your camera, but as I go through future tutorials I hope you can refer back to this post whenever you need to, to understand why I’m recommending certain settings.


It’s all about exposure

The one thing you need to understand when it comes to photography is exposure. Basically, exposure is how light or dark your image is – to achieve the. What might surprise you is that there are only three camera settings that control it:


Shutter Speed


Put together these three settings form the ‘Exposure Triangle.’ Each side of the triangle plays a role in determining the overall exposure of your photograph, but each one also has an impact on how the final image appears. A photographer’s goal is to know where to set each one to achieve the right exposure, and the artistic effect they want.

Right now this might not make a lot of sense. Let’s dive into the detail of what each setting does and how it affects exposure to make it more clear.


Shutter Speed

Shutter Speed is probably the easiest one to understand. As the name suggests shutter speed is a measurement of how long the camera’s shutter stays open for when you take a photo. A longer shutter speed lets more light in, a faster shutter speed lets in less.

But, shutter speed also affects how much movement your camera captures. The longer the shutter is open the more movement it will capture. So, if you want to capture movement (which will appear as blur) use a longer shutter speed. If you want to freeze movement (for example if you’re capturing someone running and want a crisp image of them, with no blur), use a faster shutter speed. Shutter speed is measured in seconds and fractions of seconds. So a shutter speed of 1 second would be much slower than one of 1/500 of a second.

Here are a couple of photos of my daughter on a slide that illustrate the difference shutter speed makes. The first photo was taken at a shutter speed of 1/100 – you can see that it’s blurry, as the shutter speed was too slow to ‘freeze’ her movement on the slide. The second photo was taken at 1/500 which is faster, and here you can see that the movement has been ‘frozen’ giving a crisp image.

The Three Basic Principles of Photography


Aperture controls how much light can travel through your lens at any moment. A wider aperture means that more light can travel through the lens at any moment (essentially the hole is wider), and a narrow aperture means that less light can travel through in that moment.

Perhaps confusingly, a wider aperture is measured with a smaller number, and a more narrow aperture is measured with a higher number. So, more light can come through your lens at an aperture of f2 than at an aperture of f11.

Just as with shutter speed, there’s another factor to add in here. Aperture controls the depth of field of a photograph, or how much of it is sharp or in focus. A smaller aperture (a higher number) gives you a larger depth of field, which means that more of the image is in focus. At lower apertures less of the image will be in focus.

Here are another two photographs to illustrate this. The first photograph was taken at an aperture of f3.5. You can see that the flower in the middle is in focus, but the other flowers are less sharp. The second photograph was taken at f13. Here all of the flowers are sharp.

The Three Basic Principles of Photography The Three Basic Principles of Photography


The final factor at play is ISO. ISO determines how sensitive your camera’s sensor (or the film if you’re shooting film) is to the light. A low ISO – for example of 100 – means that your camera’s sensor is less sensitive to the light. A higher ISO – for example of 1600 – means that the sensor is more sensitive. So, if all other factors are equal, an ISO of 1600 will be brighter than one of 100.

So what’s the catch? Well, ISO also affects how crisp or grainy an image is. The higher the ISO (the more sensitive your camera is to light), the more ‘digital noise’ you are likely to see – the noise gives a grainy feel to the photograph. To illustrate this I took the photograph below at ISO 3200, whereas all of the other photos in this post were taken at ISO 400 or lower – you can see how grainy this one is compared to the others.

The Three Basic Principles of Photography

Putting it all together

To take the perfect photograph a photographer needs to determine the perfect combination of ISO, Aperture and Shutter Speed they need to achieve the exposure and artistic effect that they want.

If you want absolute control over the appearance of your photographs it’s essential to understand how to manually control and balance these to achieve the effect you want. But, just having a basic understanding of these principles will help to make your photographs better – regardless of whether you’re shooting on your phone or your camera’s pre-programmed settings, as you’ll be able to make better informed decisions about how and when to use them.

In my future tutorials I’ll refer back to these settings (and this post) to help explain which settings you need for different situations, and why.


Over to you

What other questions do you have about the settings on your camera? I’d love to hear – let me know in the comments below.

Picture of Clare Murthy

Clare Murthy

I’m a newborn, baby and family photographer working with families from South West London and Surrey. I specialise in timeless, natural photography with no props or unnatural posing. I photograph babies at my studio, and families in beautiful outdoor locations. I'm based on the Surrey / London border, close to Hampton Court.
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