Whether you’re shooting dramatic landscapes or intensely focused close-ups, good photography is all about light.
You can control how much light is let into the camera by playing with aperture and shutter speed. Understanding how to manipulate these, along with ISO, will give your photographs a professional boost. Find out how with our jargon-busting guide.
One of the three pillars of photography is Aperture. Put simply, it’s the opening – or iris – in the camera lens allowing you to control how much light hits the sensor.
Aperture is measured in f-numbers, or f-stops. The smaller the f-stop the larger the hole and the higher the f-number the size of the opening decreases. So f/1.4 lets in more light than f/32.
It can be a bit confusing but if you think in terms of opposites you’ll get the hang of it. If you want to control the aperture but still need help with shutter speed and focus, set your camera to A (AV on Canon) for Aperture priority.
One of the cool things you get when playing around in this mode is the ability to impact the depth of field – the area of the image that appears sharp.
Setting the aperture to a low number like f/1.4 will give you a shallow depth of field where the main object of your image is in focus and the background is blurred – this helps the eye focus on what’s important.
Tip: portrait photography benefits from a shallow depth of field or if you’re trying to get the fine detail of a flower or plant.
By making the iris smaller you’ll increase the depth of field, putting more of the image in focus. For instance, f/22 will make the hole smaller and the depth of field greater. Keep in mind you’ll need to have the shutter open for longer to allow more light in.
Tip: open landscape or architectural scenes look best when everything is in focus, so try using a wider depth of field with a larger f-stop number.
The second of three pillars, adjusting the shutter speed can create fast moving images with blurring motion or crisply freeze the action in a moment in time. Shutter speed is how quick or slow the shutter of the camera opens to allow light in – also known as exposure time.
It’s usually measured in fractions of a second – 1/4 or a quarter of a second being slow and 1/1000 or 1000th of a second being fast. For sports photos or action shots choose a quick exposure time to capture the precise moment a football flies past the keeper. Keep in mind you’ll need plenty of natural light or a flash the faster the shutter speed because the shutter is only open for limited time.
For an ethereal photo of moving water, try setting a long exposure. You will most likely need a tripod or another way to keep your camera steady during long exposures to limit movement where you don’t want it. Another technique is panning, where you follow the subject during the long exposure. The subject stays in focus but the background blurs to slow motion.
Tip: set your priority to S (TV on Canon) to control your shutter speed while letting the camera handle the focus and aperture settings.
ISO is the final pillar of photography. It shows how sensitive your camera is to light. Typically measured in numbers, a higher number means more sensitivity to available light, while a lower number means less sensitivity.
ISO stands for the International Standards Organisation, and used to be how they rated film. The higher the ISO, the better the film performed in low light. A higher ISO will give you a better performance in low-light conditions – it’s not a replacement for a flash though. The ISO setting is controlled by your camera’s image sensor. It’s responsible for gathering light and turning it into an image, so it’s pretty important.
Higher sensitivity can distort the picture with unwanted ‘grain’ or ‘noise’. But don’t worry. Every camera has a Base ISO – the lowest ISO number of the sensor that can produce the highest image quality, without adding noise to the picture.
Tip: If you have too much noise in your photos try to shoot at lower ISO settings.
Want to learn more about DSLRs? Check out our dedicated article
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