Ring flash
Encyclopedia
A ring flash, invented by Lester A. Dine in 1952, originally for use in dental photography, is a circular photographic flash
that fits around the lens, especially for use in macro
(or close-up) photography. Its most important characteristic is providing even illumination with few shadows visible in the photograph, as the origin of the light is very close to (and surrounds) the optical axis
of the lens. When the subject is very close to the camera, as is the case in macro photography, the distance of the flash from the optical axis becomes significant. For objects close to the camera, the size of the ring flash is significant and so the light encounters the subject from many angles in the same way that it does with a conventional flash with soft box
. This has the effect of further softening any shadows.
Ring flashes are also very popular in portrait
and fashion photography
. In addition to softening shadows and creating circular highlights in the model’s eyes, the unique way that a ring flash renders light gives the model a shadowy halo which is a common feature of fashion photography.
Macro ring flash usually consists of two parts: a power and control unit mounted on a hot shoe
, and a circular flash unit mounted on the front of a lens. Power is supplied by batteries
in the shoe-mount unit, and a cord relays the power and control signals to the circular flash unit.
For larger ring flash units like those used for fashion photography, power is usually delivered by a power pack which can be battery or AC powered. Some ring flashes however, like ones made by Alien Bees, are constructed like mono lights where the light and power are contained in one unit.
Within the circular flash unit, there can be one or more flash tubes, each of which can be turned on or off individually. Some ring flashes have focusing lamps for helping low-light focusing. Also available are ring flash diffusers, which have no light source of their own, but instead mount in front of a conventional flash unit and transmit the light to a ring-shaped diffuser at the front of the lens.
There are also passive light modifiers, which will shape the light from an ordinary (shoe mount) flash into that of a ring flash. The adapters use a series of diffusers and reflectors to "bend" the light around the lens axis. The light is then emitted from that axis. This maintains any TTL lighting functions that may be shared by the camera and flash, as the actual light source has not changed.
Ring flash as a lighting technique has enjoyed a strong resurgence over the last few years, as photographers realize that it is far more useful than the one-look way in which it has been used for decades. Specifically, it is now being used primarily as a fill light to raise the illumination level of shadows created by other, off-axis lights. It is considered to be a particularly good source of fill light because it does not create harsh shadows.
Flash (photography)
A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light...
that fits around the lens, especially for use in macro
Macro photography
Macrophotography is close-up photography, usually of very small subjects. Classically a macrophotograph is one in which the size of the subject on the negative is greater than life size. However in modern use it refers to a finished photograph of a subject at greater than life size...
(or close-up) photography. Its most important characteristic is providing even illumination with few shadows visible in the photograph, as the origin of the light is very close to (and surrounds) the optical axis
Optical axis
An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens or microscope.The optical axis is an imaginary line that defines the path along which light propagates through the system...
of the lens. When the subject is very close to the camera, as is the case in macro photography, the distance of the flash from the optical axis becomes significant. For objects close to the camera, the size of the ring flash is significant and so the light encounters the subject from many angles in the same way that it does with a conventional flash with soft box
Soft box
A Soft box is a type of photographic lighting device, one of a number of photographic soft light devices. All the various soft light types create even and diffused light by directing light through some diffusing material, or by "bouncing" light off a second surface to diffuse the light...
. This has the effect of further softening any shadows.
Ring flashes are also very popular in portrait
Portrait photography
Portrait photography or portraiture is the capture by means of photography of the likeness of a person or a small group of people , in which the face and expression is predominant. The objective is to display the likeness, personality, and even the mood of the subject...
and fashion photography
Fashion photography
Fashion photography is a genre of photography devoted to displaying clothing and other fashion items. Fashion photography is most often conducted for advertisements or fashion magazines such as Vogue, Vanity Fair, or Elle...
. In addition to softening shadows and creating circular highlights in the model’s eyes, the unique way that a ring flash renders light gives the model a shadowy halo which is a common feature of fashion photography.
Macro ring flash usually consists of two parts: a power and control unit mounted on a hot shoe
Hot shoe
A hot shoe is a mounting point on the top of a camera to attach a flash unit.- Design :The hot shoe is shaped somewhat like an inverted, squared-off "U" of metal. The matching adapter on the bottom of the flash unit slides in from the back of the camera and is sometimes secured by a clamping screw...
, and a circular flash unit mounted on the front of a lens. Power is supplied by batteries
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
in the shoe-mount unit, and a cord relays the power and control signals to the circular flash unit.
For larger ring flash units like those used for fashion photography, power is usually delivered by a power pack which can be battery or AC powered. Some ring flashes however, like ones made by Alien Bees, are constructed like mono lights where the light and power are contained in one unit.
Within the circular flash unit, there can be one or more flash tubes, each of which can be turned on or off individually. Some ring flashes have focusing lamps for helping low-light focusing. Also available are ring flash diffusers, which have no light source of their own, but instead mount in front of a conventional flash unit and transmit the light to a ring-shaped diffuser at the front of the lens.
There are also passive light modifiers, which will shape the light from an ordinary (shoe mount) flash into that of a ring flash. The adapters use a series of diffusers and reflectors to "bend" the light around the lens axis. The light is then emitted from that axis. This maintains any TTL lighting functions that may be shared by the camera and flash, as the actual light source has not changed.
Ring flash as a lighting technique has enjoyed a strong resurgence over the last few years, as photographers realize that it is far more useful than the one-look way in which it has been used for decades. Specifically, it is now being used primarily as a fill light to raise the illumination level of shadows created by other, off-axis lights. It is considered to be a particularly good source of fill light because it does not create harsh shadows.
External links
- DIY Macro Ring Light Led ring light for macro photography
- Strobist.com (On-Axis fill technique, explained)