Photography school lesson 7: ISO effects

What visual effect does changing the ISO have?

  • As we have learnt, changing shutter speed or aperture can have quite a large effect on the images we produce.
  • We use these two settings as a creative tool to achieve the desired effect we want.
  • ISO is a little different to this.
  • As we know, the higher the ISO is, the more sensitive the sensor becomes. However, as the sensor becomes more sensitive, ‘digital noise’ will start to appear on your images.
  • Images may also appear less sharp, less vivid in colour and generally look a lower quality image.
  • On an ISO setting of 100, no digital noise will be visible. On a ISO setting of 3200, there will be a lot of digital noise on the image.
  • This varies from camera to camera, and every time a new update to a camera comes out it boasts better handling in low light conditions. Meaning that there is less noise even on very high ISO settings.
  • In most cases digital noise is undesirable. However, with film this noise (referred to as grain with film) was often used as an effect when wanting images to look more artistic, grungy, hand printed or textured.