The Video Mode takes a look at the how best to use ISO sensitivity when shooting video, and how it compares to taking stills. There are plenty of similarities in ISO settings between the two.
For example, sticking with lower ISO sensitivity between a range of ISO 100 – 400 will generally producer higher quality results than shooting with ISO 1600 and above.
That’s because the ISO control regulates the sensitivity of the sensor’s pixels to light by boosting the electrical charge. A higher ISO creates a brighter image but because of the increased electrical signal, the recorded images or video will be covered in digital artefacts, sometimes referred to as “grain” or “noise”.
Using ISO sensitivity: Grain
For some projects, grain can be used to good effect to create a more cinematic or artistic looking video. But as you become more experienced in video production you’ll learn that, while as photographers, we aim to get everything as close to perfect in-camera, in filmmaking, you’ll want as clean an image as possible with the maximum amount data to work with in post-production.
If you’ve recorded clean footage with low noise, you can add the precise amount that you want during the editing process.
Using ISO sensitivity: Noise
It’s good to experiment with ISO settings to find what you feel is an acceptable level of noise for the videos you’re making. There’s also an interesting quirk with some cameras, mostly Canon branded, that suggests that using ISO sensitivities in multiples of ISO 160 to reduce the impact of noise.
In short, the theory is that using these interval ISO settings decreases the impact of noise at the cost of reduced dynamic range. For more information.
Newer cameras are much better equipped at dealing with high ISO sensitivity settings though because they use clever algorithms to reduce the impact of noise.
Cameras with larger sensors and cameras designed for video such as the Canon Cine EOS also handle noise better because they have larger pixels. But all things being equal, the lower the ISO, the better the quality of the recorded image.