Studio Flash Explained
Ring lights, and ringflashes in particular, are almost a separate category of studio lighting. The studio ringflash is an outgrowth of the small circular ringflashes that are widely used by dentists and forensic scientists to photograph small items without shadows.
The principle is simple:
Instead of the light coming from one side of the camera where shadows are invariably present, a ringflash surrounds the lens. The light comes toward the subject from all angles
and the only shadow formed is a faint and thin uniform one, or none at all.
Higher-powered ringflash units have come into vogue among fashion photographers and have since stood the test of time, though traditionally very expensive and limited to the most affluent shooters.
In addition to the obvious advantage of producing relatively shadow-free images
, the ringflash can produce a certain character in lighting that is not evident with off-camera light sources.
In particular, the ringflash has a subtle tendency to add a three-dimensional look
to many subjects. This is because when the light falls on a rounded body part, say and arm or leg, the light falling on the edges is, due to the oblique angle, less reflected to the lens than the light that strikes the frontal surfaces. Since this light falls uniformly on all sides of such a feature, it appears to increase the overall appearance of depth. It is also accompanied by a nearly invisible uniform shadow that tends to separate features from one another. With off-camera lighting, the same feature would have a brighter side and dimmer side and appear more as a shadow gradient and the eye would identify it as such.
There is also the effect of inverse square law
light fall-off. When a ringlight is used relatively close to the subject (which it often is) the difference in distance from the light to the front of the subject to the back further causes the accentuation of frontal surfaces and apparent dimension.
On the negative side, direct ringflash is a small-source light and can lead to results not unlike a straight on-camera flash if not used carefully. This can produce redeye and a general “snapshot” look. These obstacles, if present, can be remedied by using a ringflash (such as the AlienBees™ ABR800 Ringflash
or the Zeus™ ZRM1 RingMaster
) that employs strong modeling lamps to reduce redeye, and by using an accessory large-source diffuser such as the Moon Unit™
The Moon Unit™ increases the effective source-size and renders a somewhat different shadow structure than direct ringflash. The shadows surround the subject more, and are thus softer and even less evident. The Moon Unit™ also allows the ringflash to be used at greater distances from the model to allow greater freedom of composition and less model discomfort because the light is softer and less blinding.
With or without the Moon Unit™, the ringflash can also provide interesting catchlights in models' eyes and is, of course, an excellent light source for many product and architectural applications.
A very popular use of ringflash in outdoor fashion work is to either overpower the natural light to produce a surrealistic balance of natural and artificial light, or to act as a natural, shadowless fill light to accentuate the subject against the surroundings. A Vagabond™ battery power supply is a likely companion to the ringflash for these uses.
In both of these uses, the ABR800 can produce f16 exposure at ISO100 10 feet from the subject (f22 at 7 feet) and is fully capable of these effects. The Zeus™ RingMaster can produce extremely intense exposures of f45 to f64 at these distances and thus can overpower an extreme amount of sunlight for the most creative uses.
A final consideration is that ringflash units such as the ABR800 and Zeus™ RingMaster can also find daily use off-camera in or out of the studio. The Moon Unit™ compares with conventional softboxes and beauty dishes and is easily mounted in tight quarters where bulkier softboxes might be difficult. The included umbrella holder accessory forms a superior concentric umbrella light. These units may also be used with the accessory honeycomb grid and gel sets for many selective lighting effects.