Exposure refers to the amount on light that hits the camera sensor. To control the amount of light, play around with the size of the lens aperture, shutter speed and external lighting fixtures.
Balance and precision are needed to ensure ideal lighting for the intended shot. With too little light, video footage can appear murky or underexposed. Trying to remedy these effects in post-production may result in more noise being added.
On the other end of the spectrum, too much light may cause highlights to be overexposed. Digital videos cannot handle high light levels, which would translate overexposed signals to flat, pure white instead.
The most direct way to control exposure is to adjust external light sources. Add more lights to the scene or dim them down. Although, when budgets are tight or the shoot is outdoors – this option would not be available.
Each camera sensor reacts to light in a different way, and that film sensitivity is measured by an ISO rating on an Exposure Index (EI).
The lower the ISO, the more light is needed to brighten an image. Slow daylight films that need lots of light would be set at ISO 100 while fast film indoors would require ISO 800. An ISO rating of 200 would need half as much light as ISO 100.
Large-sensor cameras like the Sony F3 have high native ISO ratings of 640 or 800, but as ISO is increased, electronic gain would likewise increase – resulting in much noisier video footage. Test equipment under different lighting conditions first to ensure it does not affect the end product.
Other ways to control the amount of light include adjustments to the lens aperture and affixing a neutral density filter to the camera. Neutral density filters cut out light without affecting color temperatures.