You need to think carefully before making a choice here because noise reduction works by softening the image, which reduces noise, but at the expense of image detail. Most cameras offer a choice of noise reduction settings – usually low, normal, high and off.
The image above was taken at ISO 200 while the image below was shot at ISO 1600.Īt print sizes less than A4 it's hard to pick the difference, but zoomed in to overĤ00%, as is the case here, you can clearly see that image below contains more noise. Similarly, if you’re shooting sport a higher ISO can help you obtain a faster shutter speed to freeze the action. As the light dims, a higher ISO will help you keep the shutter speed up without the need to add artificial light, such as on-camera flash.
If you’re shooting outdoors in good light, it’s generally best to use your camera’s lowest ISO setting – 50, 100 or 200 ISO.
Some high-end pro DSLRs produce great images at 12,800 ISO and beyond. While compacts can get very noisy at 800 ISO, most entry-level DSLRs produce relatively clean images at 3200 ISO. The good news is that most DSLRs – even the cheaper models – offer better noise performance than compact cameras. At high ISO settings it can be so bad it’s a struggle to make out important details – like watching an old TV with bad reception. Noise is present in all images, though at low ISO settings it’s usually not visible unless you zoom right in to the smallest details of the image. Noise, in this context, has nothing to do with the beeping sounds your camera makes when it focuses! Rather, it describes those dots and coloured artefacts you see in some images. It’s important to understand that as ISO increases, so too does image noise. Conversely, as ISO decreases the sensor becomes less sensitive, and you need more light to make an exposure. As you increase ISO the sensor becomes more sensitive (also referred to as “faster”) so you need less light to make an exposure. The ISO control changes your camera sensor’s sensitivity to light. In the following weeks we'll look at shutter speed and aperture. This week James Ostinga and Andrew Fildes focus on ISO. There are really only three camera controls you need to understand – aperture, shutter speed and ISO.