When photographing portraits, it is important to start with one light on the subject and build from there. The closer the light is to the subject the softer and more diffuse it will be.
- The key light should be large and close to the subject. The light should be placed at a 45-degree angle from the subject.
- Next position the fill, hair and backlights. The fill light will be at the same angle on the opposite side of the camera from the key light.
- It is important to determine the ratio to be used for the portrait. Take the first light reading from the subject's face aiming the meter towards the camera lens. The lighting ratio will depend on the type of portrait lighting to be used.
- 4:1 ratio is a common for studio portraits. This is dramatic lighting. (2 stops)
- 3:1 ratio is good for general portraits. This is defining light, but less dramatic than 4:1 ratio. (1 1/2 stops)
- 2:1 ratio is good for corporate headshots and general portraits. There is very little shadowing on the face, but still some contrast on the fill side of the face. (Not much, just some) (1 stop)
- 1:1 ratio is flat lighting. Not good for portraits. The light flattens the face and loses most of the definition and shape of the face. (Even)
Generally, 4:1 or 3:1 will render a good studio portrait. Measure the key light from the subject's face and set the fill light two stops from the key light for 4:1 ratio, 1 1/2 stops for 3:1 ratio.
To meter for the ratio, meter the shadow side of the face, compare with the first meter reading on the light side of the face and make sure it is a little less than the correct ratio. Now, move the reflector in and take another reading. Keep moving the reflector in and out till the proper ratio is reached. For example, if the meter reading off the key light is f/11, then the shadow side of the face should read f/5.6 for the proper 4:1 ratio.