Placement of main and fill light?

Started Jan 21, 2004 | Discussions thread
Chuck Gardner Forum Pro • Posts: 10,381
Lighting 101

Let's start basics for the key or main light. It's function is to create the shadows and the illusion of depth in our 2D medium. You get shadows by placing the key light in front and to the side of the subject.

The nose shadow is a good "telltale" or barometer of main light placement. For good 3D modelling you want the nose shadow to fall down and to the side opposite the light. Starting with the light about 45 degrees from the camera axis (imaginary line between the camera lens and the subject it is pointing at) and 12 or more inches above the subject is a good starting point.

Which side to put the light on? That depends on the pose (angle of the face as seen from the camera) and the desired lighting effect. It also depends on the person's features; most people have a "good" side.

Having the face straight ahead (full face) will produce similar (but opposite) lighting on the front of the face if you move the light from one side to the other (from the aforementioned 45 degree position). What does change is the side of the head which is in shadow. Thus, if a person has a "good" side (i.e., better than the other one) you'd want to put the key light on the good side and hide the "bad" side in the shadows. In general only people with narrow, very symetrical faces (e.g., models) look best full face.

The second basic pose is the 2/3 view. Here the subject turns their head sideways to the camera until the profile of the rear eye socket and cheekbone is visible. In otherwords you don't want to see much skin (i.e., the side of the face) behind the rear eye. You don't want to cut the eye in half either. With this pose which side the light is on makes a BIG difference.

If the subject is looking towards the key light it will fall on the front of the face and into both eyes, producing catchlight reflections of the light which give the eyes sparkle. The broad side of the face turned towards the camera falls into the shadows. Overall the 2/3 pose, combined with this "Short" lgihting on the face will make the face look much thinner than full face, especially for subjects with round face.

If the subject is looking away from the key light the broad side of the face, and the ear (if visible) but only half of the front of the face will be illuminated. This "broad" lighting makes the face look very wide and having half the face in shadow is not my idea of a good portrait.

Now for the fill. It's not rocket science. Its function is to lighten the shadows created by the key light to within the range the camera can record, and what looks natural. By changing the intensity of the fill relative to the key light (i.e. lighting ratio) you can alter the mood of the photo from dark and introspective (e.g., portrait of an old man or firefighter) to light and fresh (e.g., children or a bride).

The conventional, and some might say logical, place to locate the fill lght is next to the camera so it will fill all of the shadows the camera sees. One can also place a fill light on the side opposite the key light, but this may create secondary shadows or muddle the modeling of the features created by the key light. Since you are starting out, I'd suggest keeping it near the camera.

If you are using a reflector for fill, alone or to in addition to a fill light, it obviously must be positioned somewhere it can catch and reflect the key light. That means on the side opposite the key light, or a north-facing window if using daylight. If you start to get highlights from the fill panel in your shadows it is too close.

As for whether to use white or silver for the key and fill, it depends on the lighting effect you want. Bouncing into white, or shooting the flash through it, will produce softer highlights and shadows than the silver, which is more focused and specular.

The color of the background influences lighting. Its difficult to create a true high key with only two lights because one of them needs to be used to illminate the background. Even low key (dark field) photos benefit from having a separate light dedicated to controlling the appearance of the backdrop.

A fourth light on a boom over the subject, on the side opposite the key light is often used in portraits to create a highlight in the hair on the shadow side and provide enough rim light on the head and shoulders to separate a dark haired / clothed subject from a dark low key background.

Chuck Gardner

Steve wrote:

I just got my two AB800 and two umbrellas. I read the posts on this
and there are so many opinions as far as the placement of the main
and fill light with the relationship to the subject. I have one
white and one silver umbrellas. Can someone shed a "light" on the
Steve Provisor

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