The rise of modern technology has inspire more the cinematographers to learn more and made it easier in greater the art of lighting. The light meter is the original ratio tool. This helps to read the light ratio. For the key light is fairly straight forward process to measure the ratio. you take a reading of key side in a shot and then the reading of the fill side of your shot.  

Lighting Setup 

Key Light

Produces the most amount of light and shines on your subject.

Fill Light

This ‘fills’ in any shadows left by the key-light.

Back Light

Beautifies the image with a soft glow on the back of the subject’s head/shoulders. For any sort of interview or video with someone speaking in front of a camera.

Turn off all lights before starting. This way, you’ll be able to properly see what each light is doing.

Key Light:

The key light is your strongest light. There is no standard wattage that is typical for a key light. It can range from 150 watts to 10k watts depending on the situation.

The fill light is used to ‘fill’ out the shadows created by the key light. This light is less powerful than the key light.

This light is placed on the opposite side of the camera as the key light and shines on the subject at a similar angle. These shadows can be created by a person’s nose, cheek, eye- sockets and chin.

Fill Light:

The key light lights the subjects face and front side of the body. The reason we put it at an angle rather than directly in front of the subjects face is so we have a difference in lighting on one side of the face compared to the other. This is very pleasing and creates a more dramatic/interesting look.

Back Light:

The back light increases the quality of your image ten-fold. Placing the back light as close to directly behind the subject as possible by being aware of what your camera is seeing though. .This light creates a nice ‘halo’ effect around the subject’s shoulders and head. This separates him or her from the background and gives the shot more depth..