Tips for Understanding and Mastering Exposure

On this basic video, by Pye from slrlounge looks at some of the fundamentals of exposure – the aperture and the ISO – what they mean and how they effect your image.

The lens aperture controls the amount of light that enters your camera and hits the sensor. The more open it is the more light gets inside. It also has an effect on how much your image is in focus (and how much is blurred out – something that you can use as an artistic tool – for example for shooting a portrait with a blurred background).

ISO is a property of the sensor – it allows you to artificially increase the amount of light the gets to the sensor (it actually boosts the signal strength as you can’t create more light). This allows you to shoot in lower light places (or at higher shutter speeds) hoever the higher the ISO the lower your image quality your sensor will produce (typically larger sensor perform better in lower light as they collect more due to their larger size).

One thing which is missing from this video (and is probably discussed elsewhere in this 101 series) is the importance of the shutter. The camera shutter is the third part of the exposure triangle (which we have covered on photographer John Greengo video “The Exposure Triangle in Action: Shooting an Eagle Landing“).

You can find many more helpful photography tips on our Photography tips section here on and  LensVid.

Iddo Genuth
Iddo Genuth is the founder and chief editor of He has been a technology reporter working for international publications since the late 1990's and covering photography since 2009. Iddo is also a co-founder of a production company specializing in commercial food and product visual content.

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