Produces the shadows that give the photo a three –dimensional appearance.
Appropriate when ambient is relatively even. It adds “snap” to cloudy-bright outdoor photography.
Provides details in shadow areas. Remember fill light will add to the ambient light, so overexposed highlights will sometimes occur.
Appropriate when the existing light produces dark shadows. Think fill flash on a sunny day.
Applied when you want light in a specific region of the photograph to draw the viewer’s attention.
When used as a background light, be sure the exposure compliments the key light exposure. When used as a “kicker”, use a gobo* to minimize lens flare.
Outdoor Fill Lighting: Whenever you attempt to balance flash with ambient, you have to consider the contribution the fill light will make to the overall exposure of your subject. When photographing for a newspaper, one should try to keep the contrast between the highlights and the shadows to a minimum. Deep shadows ultimately become large blobs of black on the printed page. Fill light will go a long way in cutting the contrast. But be careful: the addition of fill light not only brightens the shadows but also adds the the brightness of you highlights. Over-filling the shadows often results in overexposed or "blown" highlights.
You can avoid the blown highlights by underexposing your subject slightly and allowing the fill light "take up the slack". In this photo, I decreased the metered exposure by about 2/3 of a stop before apply a TTL adjusted at my normal +2/3 stop. The shot, incidentally, was done at very close range using a wide angle lens. Keeping things level minimizes the disturbing effects of perspective distortion.
Accent Lighting: Accents can be added to provide additional detail in the background. You have a little more freedom about coverage, just a puddle of light to add some detail to the image. Certainly, we see accent lighting and accept that perfectly even lighting is not only difficult to create, but just a little boring.
In this case, I used my usual Zumbrella for the foreground lighting. I noticed that the light fell off quickly, due in part to the angle of the wall. I placed a second remote SB-800 on a nearby staircase and aimed it directly at the painting, perpendicular to the surface. I didn't have a grid at the time, relying on a narrow beam angle adjustment to contain the light. It wasn't entirely successful because there is a definite hot spot below the center of the painting. If I had the time I could have fixed this, but with dinner guests just minutes away, my timely exit was probably more appreciated.