Iris/Aperture
In a movie camera this is called the iris, in a still camera it is known as the Aperture. The aperture and iris is a mechanical opening inside the camera that allows the user to control the amount of light that passes onto to light sensitive chip and therefore altering how bright the image is. When the opening is large, a lot of light can pass through making the image bright. When the opening is small, less light passes though making the image dark.The side effect of opening the aperture is that the depth of field becomes shallower making it more difficult to focus but can create stylistic effects.
Aperture values range from values like 1.8 to 32. 1.8 is a large hole to allow light through, 32 is a small hole.
Shutter Speed
This describes how much time the light sensitive chip is exposed to light for. When the chip is exposed for a very short time the resulting image will be darker than if the chip were exposed for a long time.
The side effect of a long exposure time results in an image that is less clear because of the movement that has taken place during that time. A short exposure time results in clearer images because less STUFF has happened during the time of the exposure.
Shutter speed values start at 25-50 for video and can range up to 10000. 25 refers to a 25th of a second (1/25) or 0.04 as a decimal, this is a long time. 10000 is 10000th of a second and is a very short amount of time, great for fast moving objects or people.
Gain/Film speed
Gain in a video camera, Film speed for a still camera. The gain forces the camera to increase it's sensitivity and results in a brighter image. The film speed in a still camera does exactly the same but is measured in ISO, a relic from the analogue age.
The side effects of increasing gain or film speed results in an image that is noisy. Try to leave this value at the lowest possible setting (0DB or 100-400 ISO).
