cgardner
Offline
Image Upload: Off
|
 p.1 #4 · RRS B87-B Flash Bracket | |
Bouncing can work, but there's not always a suitable surface to bounce the light off of. Even if there is the huge loss of light energy and unpredictability of the results make the odds of great results about as predictable as a three-cushion bank shot in billiards made blindfolded.
The thing to realize about lighting is that the angle of the light is the critical variable for creating the illusion of 3D. Most objects have the most realistic 3D rendering when lit from behind and to the side (just consider the phases if the moon and where the sun is relative to the moon to create them). I find about 135 degrees from the camera axis to be the "sweet" spot for 3D rendering of still life objects, with detail revealed in the front with sky-like neutral fill from over the camera. I have a bias towards natural looking lighting.
A human face creates an entirely different set of lighting considerations and problems. The most important element of human interaction is eye contact, or more specifically seeing whether or not a person meets your eyes or diverts theirs, and what expression their mouth forms. So in a photo where the goal is for the person in it to appear open and willing to engage its necessary to get light past the overhanging brow and nose in the middle to get light in the eyes.
The human brain recognizes faces and objects in photos entirely by matching patterns of contrast with stored memories of seeing objects which have also been handled. Its why we give infants basic geometric shapes in bright colors to play with, to program their brains to recognize those patterns. Thus there are some lighting patterns which make a face easier to recognize than others. Since the sun and most artificial sources are up above the head most people are conditioned to recognize faces lit that way as natural.
The biggest problem in lighting a face in a natural flattering way is the nose and the shadow it casts. Our perception of shape from a 2D photo comes primarily from the shape and placement of the shadows. For example on a map the mountains are depicted by just drawing the shadows they would cast when the sun is at a 45 degree angle. So when lighting a face there are two considerations with respect to the nose to make it appear natural and non-distracting: the size and shape of the nose shadow and where it falls on the front of the face, and how dark it is. The first is a function of key light placement, the second a matter of fill direction and intensity relative to the key light.
Over the centuries portraitists have tried every conceivable combination of key light and fill positions and have only found a few which are able to render a human face slim and symmetrical with natural modeling, with light in both eyes and a non-distracting nose shadow. Your odds of creating any of them with two flashes on the same bracket are slim to none, with the possible exception of shooting macro shots of Barbie dolls.
The problem with two lights on the same bracket is that as shooting distance increases they appear from the position of the subject's face to be a single flat light source. So what you will wind up with at distances of 7-9ft which produce normal perspective on human faces is slightly crossed flat lighting; no better and actually worse in terms of natural modeling than a single flash directly over the lens.
To meet the criteria for flattering natural looking lighting - in both eyes and mouth area, natural modeling of cheeks, no distracting nose shadow - the off camera "key" light needs to be placed about 45 degrees off to the side of the nose and about 30 degrees above the eye line to create a "short" lighting pattern for an oblique view (the combination which makes a face look slim and symmetrical), or in a full face pose directly above the face in line with the nose for a "butterfly" pattern which complements a full face pose with perfectly symmetrical lighting. There are many other possibilities of course, but those two for oblique and full face views are the most flattering for the greatest range of facial shapes.
The most effective overall lighting for people comes from combining the two "still life" and "flatter the face" strategies. First model the face in a natural way with light from a downward angle with reaches the front of the face, eyes and mouth; then place another light source behind and to the side to rim-light the overall shape of the head and body and separate it from the background. That can actually be done effectively with just two lights if the frontal lighting is kept raised and centered in the "butterfly" orientation and diffused a bit.
So in practical terms the more effective hot shoe strategy is to keep one flash on the camera above the lens and put the second on a stand you can easily move around in a candid situation. If you see a person will be standing still and looking in a predictable direction its possible to position the off camera light for short lighting:
In other situations where the direction of the nose (the biggest nemesis to flattering facial lighting) can be controlled or predicted the off camera light can be wheeled behind the subject for rim light, which also adds a nice 3D illusion to the lighting
The light from the front is provided, at a flattering downward angle, from the flash on the bracket. More importantly there are no distracting shadows because most are hidden behind the subject and below / behind the nose. That "park the light behind" is pretty much a no-brainer when using ETTL flash and is also great for capturing action, such as on a dance floor at the birthday party full of frenetic five-year-olds:
In situations where use of two lights isn't practical the single centered "fill" flash on the bracket provides light from a flattering direction.
Having the second light off the camera is really the key factor for creating the illusion of 3D and will ALWAYS produce more effective and much more predictable results any strategy relying on bounce for the simple reason bounce is inefficient and unpredictable. So as I see it, whether to use an off camera flash or not is always a compromise between results and convenience and the solution is to make the use of the off camera flash more convenient. Most seem to dismiss the idea of an off camera flash because they envision mounting it on a conventional stationary stand. My first job out of college was assisting Monte Zucker, who introduced and popularized the two-flash strategy in the early 1970s. He hit on the rather brilliant idea of putting the off camera flash on a converted IV stand. Those stands have five compact wheeled legs and are very stable. They can be easily wheeled anywhere with one hand. I did it for several years shooting wedding receptions and still use an IV stand for all my hot shoe location shooting. While not as convenient as single flash, its not really inconvenient either and I find the results, in terms of lighting effects and predictability of results, well work the effort.
So after your dual flash on bracket experiments, try that approach next 
Chuck
|
