Basic Settings

This section provides a high level overview of aperture, shutter speed and ISO - including what they are and how they are measured. You will often hear this referred to as 'the exposure triangle'. Having at least some understanding of these key aspects of photography is going to be extremely useful before you start taking photos — and this knowledge is equally relevant regardless of your camera make/model.

 

Links to more detailed information can be found throughout.

 

 

What is a sensor?

This is an important point to mention before we start talking about aperture, shutter speed and ISO. The image sensor is the part of the camera which captures light, creates the image and sends that 'data' to the memory card. Different cameras have different sized sensors, which need slightly different settings.

 

Click here for more info on what sensors are and why they matter:
www.gillprince.com/what-is-a-sensor

 

 

What is aperture?

The aperture is the size of the hole in the lens, which determines how much light can get into the camera and hit the sensor — so your shot is correctly exposed (not too dark or too light). Aperture is usually referred to as being 'wide' (a big hole) or 'narrow' (a small hole). Aperture is also one of the things that controls 'depth of field', which is how much of your image is in focus from front to back — i.e. from the closest thing to your camera, to the furthest thing you can see.

 

Click here for more info on aperture:
www.gillprince.com/what-is-aperture

 

 

Why does depth of field matter?

When you have 'shallow' depth of field, only the object you are focusing on will be sharp (e.g. a person in a portrait). Anything in front of it or behind it will get progressively more blurry. This effect is achieved by using a wide aperture — so a large hole in the lens. A 'deep' depth of field is when everything is in focus — from the closest element to your camera, to the furthest thing you can see — and this is achieved with a narrow aperture, so a small hole in the lens.

 

Click here for more info on depth of field:
www.gillprince.com/what-is-depth-of-field

 

 

How aperture is measured

Aperture is measured in 'f numbers' or 'f stops'. The f numbers available will vary depending on your lens, but the most standard set is:

 

f3.5, f4, f4.5, f5, f5.6, f6.3, f7.1, f8, f10, f11, f13, f14, f16, f18, f20 and f22

 

As they are fractions, they are back to front — so a small number is a big hole and a big number is a small hole. This can take some time to get used to! Many compact and bridge cameras go from f2.8 to f8, so don’t worry if your camera doesn’t have an f number which is higher than that.

 

 

How zooming affects aperture

It's worth mentioning at this point that, when you zoom in to photograph something in the distance, the size of your aperture will reduce. This is due to the mechanical construction of most standard lenses.

 

So on an 18-55mm 'kit' lens for example (which most entry level cameras have) you can set an aperture of f3.5, but if you then zoom in as far as the lens will go, the size of the aperture will reduce to f5.6. So if you can't get your aperture value to go as low as you think it should, you are probably slightly zoomed-in! Different lenses have different minimum apertures when at full zoom.

 

 

What is shutter speed?

The shutter sits in front of your sensor, a bit like a pair of closed curtains, but top and bottom rather than left and right! When you take a shot the shutter opens, lets in some light, and then closes again. This controls how much light hits the sensor, in tandem with the aperture setting.

 

How long the shutter stays open for is known as the 'shutter speed' or the 'exposure time'. You will hear people talk about fast shutter speeds/short exposures, or about slow shutter speeds/long exposures — and these terms mean the same thing.

 

Click here for more info on shutter speed:
www.gillprince.com/what-is-shutter-speed

 

 

Why shutter speed matters

If your hands move while the shutter is open, the camera will also move (known as 'camera shake') and your shot won’t be sharp. This is why it's vital to control your shutter speed for every shot you take — as there is no way to fix a blurry photo! The same can also happen if your subject moves while the shutter is open.

 

Camera shake is also more likely to occur if you're using a telephoto lens and are 'zoomed-in' on a small part of a scene, as any movement is magnified. You can however get some great artistic effects with very slow shutter speeds.

 

Click here for more info on long exposure photography:
www.gillprince.com/long-exposure-photography

 

 

Which shutter speed to aim for

Shutter speed is measured in fractions of a second — e.g. 1/50, 1/100 or 1/1000 and so on. A hundredth of a second (1/100) is generally considered to be a point where you can hand-hold the shot without your hands moving, so always aim for this as a minimum. Though, as already mentioned, you may find you need a faster shutter speed if you're using a long telephoto lens.

 

If your shutter speed is less than 1/100 (e.g. 1/50) you risk ending up with a blurry shot — and if your subject is moving, you need an even faster shutter speed to avoid motion blur — e.g. 1/250 or more.

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Standard shutter speeds

Going faster from 1/100, the usual set is:

 

1/125, 1/160, 1/200, 1/250, 1/320, 1/400, 1/500, 1/640, 1/800, 1/1000, 1/1300, 1/1600, 1/2000, 1/2500, 1/3200 and 1/4000.

 

Some cameras can go much faster. Then going slower from 1/100, the usual set is:

 

1/80, 1/60, 1/50, 1/40, 1/30, 1/25, 1/20, 1/15, 1/13, 1/10 and so on into whole seconds.

 

Whole seconds will be shown on your camera with double quote marks after the number — e.g. 2" is 2 seconds.

 

 

Balancing aperture and shutter speed

Aperture and shutter speed work together to let in the correct amount of light, but there is always more than one 'right answer' for any shot you take. You could use a wide aperture and a fast shutter speed (big hole, for not much time) or a narrow aperture and a slower shutter speed (smaller hole, for more time) and the exposure would be exactly the same. It's a bit like a seesaw — if one side goes up, the other side has to come down, to allow the same amount of light to hit the sensor.

 

Click here for more info on the relationship between aperture and shutter speed:
www.gillprince.com/balancing-aperture-and-shutter-speed

 

 

What is ISO?

In simple terms, increasing your ISO amplifies the signal between the sensor and the memory card, giving you a brighter image without having to change your aperture or shutter speed. When light levels are low, you may find that your shutter speed is too slow to hand-hold the camera, which is when you will need to raise your ISO. This can reduce image quality, which is why you wouldn't just do so all the time — but don’t be scared to raise it if you need to.

 

Click here for more info on ISO, what it is and when to use it:
www.gillprince.com/what-is-iso

 

ISO is useful for situations where you are taking photos in low light, as you can use a faster shutter speed than would otherwise be possible and still correctly expose the shot.

 

 

How is ISO measured?

The base level on most cameras is 100 ISO, but some go as low as 64 and others start at 200.

The standard scale is to double it each time — so 100, 200, 400, 800, 1600, 3200 and 6400. More modern cameras go much higher than older ones — i.e. 25,600. Some cameras can also be set to 1/3 ISO increments which gives you more flexibility, so if your camera has more numbers than listed above, this will be why.