ISO controls the level of sensitivity to light. The lower the ISO, the less sensitive it is to light. Accordingly, the higher the ISO, the more sensitive it is to light. So, you would use a lower ISO, like 100, in bright daylight. On the other hand, if you only have a limited amount of light to work with, such as when shooting indoors or at night, you can up the ISO. However, it’s better to keep the ISO as low as possible since footage will become noisier at higher ISO levels. (Noise refers to the grainy multicolored specks that can appear in images.)
Before shooting important footage, run some tests on your camera to find out what are the optimal ISO levels.
ISO 100
ISO 6400
Videography:
With video, a slower shutter speed (smaller denominator) produces more blurring, and the video will appear smoother. A faster shutter speed (bigger denominator number) will have more crisp images, and objects in motion will appear more jittery. In addition to objects in motion, this also applies to when you’re panning the camera.
The general rule of thumb for setting the shutter speed for video is to double your frame rate to get the denominator of the shutter speed. So if your frame rate was set for 24 frames per second, you’d use the shutter speed that’s closest to 1/48 since 24 x 2 = 48. This is called the 180 degree shutter rule. As always, rules are meant to be broken. If you’re going for a certain aesthetic you can always play with the shutter speed. You might want to set the shutter speed higher for a more stuttered look or lower your shutter speed for a more blurred effect.
Additionally, if you’re filming lights and notice some flickering or if you’re filming a monitor or television set and see scan lines, adjusting the shutter speed will help reduce the light flicker or monitor scan lines. Whatever the case, you should generally use the same shutter speed throughout your entire video project.