Use your lens’ focal length effectively: are you getting enough light?

Your lens' focal length and light: 17mm

Confused about how to use your lens’ focal length when composing photos. This quick guide shows you the impact your focal length has on photo composition, and the merits of each.


Choosing the right focal length is as important as choosing the correct aperture and shutter speed. As well as determining how much of a scene you get into your frame, focal length also contributes to the composition and overall feel of images.

Choosing your focal length should be a decision based on a lot more than how much of your subject you want to include in your shot.

For example, if you were photographing a beach with some driftwood in the foreground this would look wildly different using a wide angle lens – where distance would be exaggerated and far subjects would appear smaller – and a long lens, which would compress distance without shrinking subjects.

Using a wide focal length

Nicki Pardo / Getty Images

Using a wide focal length
You’ll get great depth of field and fit much more into your frame, creating intimate-feeling shots.


Using a long focal length

Guy Edwardes / Getty Images

Using a long focal length
Pick out your compositions carefully, isolating and compressing whatever grabs your attention.

Your lens’ focal length vs light

Your lens' focal length and light: 10.5mm


Your lens' focal length and light: 17mm


Your lens' focal length and light: 35mm


Your lens' focal length and light: 70mm


Your lens' focal length and light: 200mm


Working a cool photo location with a nice, long zoom? Then keep an eye on the amount of light coming into your shots.

For example, the 17mm shot in this sequence required a shutter speed of 1/180 sec, as there was lots of light from the sky coming into the lens.

Zoomed into 200mm, however, and there’s no sky, so the aperture was opened to f/2.8 and a shutter speed of 1/500 sec was employed.

These were all taken from the same spot, to show the impact of different focal lengths.


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