What is ISO? Understanding ISO for Beginners – Photography

👋 Hi Everyone and welcome to our We Are Raw Photography Guest Article! We here at We Are Raw Photography love to support our photographers and that’s why we monthly publish a guest article from our photographers. In this article, we welcome Josh from our Facebook group who is the winner of our photography knowledge quiz and talks about ISO in photography. Please feel free to share some photography love and friendship in the comment below.

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What is the equivalent of film speed in digital cameras?

ISO in photography is a measure of sensitivity, the higher the iso number the more sensitive the film is, in the case of digital the sensor signal is amplified more and more the higher the iso setting. And that’s where noise comes in, I think of it like an old school tube amplifier for music when you turn it up and you get that hiss between songs is the equivalent of the noise in high iso photos!

Josh Cundy
guest Article from our photography quitz winner

The ISO setting is often misunderstood but it is actually pretty simple.

  • ISO in photography is a measure of sensitivity to light, back in the film days you could buy different films for different situations, 100 for general use purpose with sunshine or very good light, 200 for when it was cloudy 400 ISO, for let’s saying action, and you could even get 800 ISO, which would have been for low light or faster shutter speed but the shots would appear grainy. Some still use film in hobby/specialist applications passionately. That’s how things worked in the film days but now we are in the digital age.
  • Getting back to ISO and what it means in digital photography, it is a measurement of how sensitive to light your image sensor is. If we turn the ISO up too much we run the risk of noisy photos, hang on, what the hell is noise in a photograph???
  • When you turn up your ISO because of low light or the need for fast shutter speed to freeze the action you are amplifying the sensitivity of your image sensor which can lead to digital noise. I like to think of it like an old school tube valve amplifier, where you rocking your tunes loud and then the song ends and you get that hiss/noise between songs, this is the same thing except we get digital noise that shows as a grainy unsharp, textured looking images because the image signal is being amplified so much.
  • So the best advice I can give you would be to use fast lenses, keep your ISO down as low as possible while still allowing the desired shutter speed.

To sum it up, ISO is a measure of sensitivity, and if you push it up too much you will get noise in your photos. When possible use a tripod so you can be steady for a longer shutter speed but without the noise, as u will be able to use a lower ISO setting. I hope this helps you to understand ISO.

Here is an image shot from Josh on a tripod to keep the ISO down to as this was a 30 second exposure – I call this shot under the bridge.What is ISO Understanding ISO for Beginners Photography - We Are Raw Photography

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