Photography Lighting and Photographic Lighting - 'True' fill light for photography
Ok, this is more of a technical subject, but I think that it’s worth the electrons as a topic of discussion. Pretty much every photographer understands photographic lighting enough to know the concepts of main light and fill light in ordinary photography lighting situations.
The main light, in photography lighting, gives the subject, shape and form. Probably the biggest decision is lighting a subject is deciding where to optimally place the main photographic light. On some subjects, an inch left or right, or up and down, can make or break the shot. Don’t get me wrong, on many shots, and inch or two in the light’s position, does not make much of a difference, but in some shots, especially food photography, an inch can make a huge difference in the quality of the photograph. We’ll talk more about that at another time.
The other, lesser thought of light source, is the fill light. When most photographers set up their lights, they will place the main light to one or another side of the subject and the fill light will usually be placed very near the camera, most likely on the opposite side of the camera as the main light. The idea being that the fill light is meant to ?fill’ in the shadow of the main light. The intensity of the fill light is increased or decreased to give the subject matter the desired "light ratio". Right? That’s right. The problem is that the fill light that is meant to ONLY fill the shadows, but in reality, it ends up casting it’s own shadow and there are usually large areas of the image that the fill light never reaches. Don’t believe me? Try shutting off you main light and take a picture using just your fill light. You will notice that the fill light doesn’t really fill, especially areas "under" the subject. If the subject has any type of overhang, like a plate lip, for example, that shadow area ends up being in shadow from both the main light and the fill light, making it totally "un lit".
Ideally, the fill light should surround the camera, theoretically, casting light from below, above, and from both sides of the camera "filling" in everything and not casting any shadows of its own. The ideal light would probably be a really big "ring light", but in reality, most ring lights are too small and end up casting their own shadows. In food photography, you can see the lack of fill light in a very textured subjects like a salad, for example. Each leaf of the salad acts as a little awning, preventing the main light and the fill light (any light from above the camera axis) from actually getting to the shadow areas. The result is very very dark shadows. What’s the solution? Glad you asked?
Years ago, I bought a 10’ x 10’ sheet of material from Chimera, the company that makes the light boxes. The material is the same material that my light boxes are made from, so in theory anyway, the light that I transmit trough the material is the same color temperature as my light boxes. I hang the material directly behind my camera and project two lights from behind and trough the material. The lights are far enough apart from each other so that the hanging material works as a 10’ x 10’ light box. The big advantage of the is light is that some light ends up coming from below, above, and around the camera, making it a "true" fill light. The camera and food photographer does obstruct some of the light, but a portion of the light does und up coming from slightly below camera axis, filling in any ?awning? areas in your photo. It really makes a difference. Try it yourself.