three point lighting is a method for illuminating a subject in a scene with light source from three different distinct angles. the three different types of light are key light, fill light and backlight.
key light:
- this is the main and strongest light that is responsible for exposure. it is placed to one side of the camera/subject so that one side is well lit and the other has some shadow. the key light is the one that has the most influence on the look of the scene/image. placing it to the side of your subject will help to create some dimension and depth. depending on how far off centre you place the key light, your scene/image will be anything from a high-key image to a low-key image.
fill light:
- this light is the secondary light and is placed on the opposite side of the key light. because the key light creates shadows, the fill light is then used to fill the shadows created. it is usually slightly further away from the subject than the key light as it is softer and dimmer. the fill light can also help reduce the overall contrast of the scene if needed. this light and the key light work together to determine the mood of the image/scene you're creating.
backlight:
- this light is placed behind the subject, lighting it from the rear as its purpose is to provide definition and subtle highlights around the outlines of the subject, rather than providing direct light like the others. this light can also be placed off to one side, directly behind or overhead as long as it is still behind the subject. the back light helps to separate the subject from the background so that they don't disappear into it, this provides a three-dimensional look.
how to achieve it?
- the 'standard' three point lighting setup typically has the key and the fill light set up at about 45 degrees to either side of the subject with the camera in between them.
the backlight is then usually placed behind the subject, opposite the key light just outside the frame. this creates separation since that side of the frame would be darker.
why do we use it?
- we use three point lighting because it comes from our natural and artificial spaces. we have to be lit by at least one light which is the light that gives us exposure - the key light.
when moving around, we are hit by various light sources. when we turn our backs to the sun, it hits us from behind, this is backlight. backlight causes a rim of light behind the subject which cuts it out from the background.
references:
https://www.mediacollege.com/lighting/three-point/
https://wolfcrow.com/what-is-three-point-lighting-and-why-do-we-use-it/