Frequently used for close-up photography, a light-emitting diode (LED) ring light typically consists of a doughnut shaped frame containing LED lights arranged in a circle. Fitting over the camera lens, this type of lighting provides shadow-free illumination. LED ring lighting designs are available in many sizes with varying styles of lights. Functionality and power source options of the devices differ along with price. In addition to macrophotography, LEDring lights have numerous industrial uses.
While an LED ring light consistently has a circular patterned light arrangement along with a circular inner frame diameter, the outer perimeter of the frame may be circular, square or hexagonal. Some frame housings contain thumbscrews that readily attach to varying sizes of camera lenses, while other apparatuses contain interchangeable threaded inner diameters that screw directly onto the camera. LED rings generally fit lenses ranging in size from 1.9 inches (about 49 mm) to 2.7 inches (about 70 mm) in diameter, but special order lights can fit diameters anywhere from 1.3 inches (about 33 mm) to 30.5 inches (77.4 cm) in size.
The light intensity and color depends on the bulbs used in a LED ring light. A photography ring light may contain as few as 12 LED bulbs, 0.31 inches (about 8 mm) in size, or as many as 144 LED bulbs, 0.1 inches (about 3 mm) in size. While the 12-bulb version has one ring of lights, larger units can contain up to five concentric rows. Manufacturers design LED bulbs in every color of the visible light spectrum in addition to making infrared or ultraviolet bulbs. Units are also available with diffusers or reflectors, which photographers use to soften or focus illumination.
Various designs allow for varying degrees of LED ring light function. A simple LED ring light merely turns on and off; more complex versions separate the rings into halves or quadrants. Photographers may then turn each section on or off individually or control the light intensity. While a camera hot shoe provides a strobing light flash, manual control switches provide greater diversity of function.
Power sources for ring lights are also versatile. Many use AA or built-in lithium batteries and some units come with alternating current or direct current adapters. Large, expensive professional LED light rings plug directly into the wall. Prices vary widely by size and quality, but creative individuals can construct a do-it-yourself (DIY) LED ring light for a fraction of the cost.
As LED ring lights typically use very little power, emit virtually no heat and last longer than incandescent or fluorescent bulbs, numerous industries employ the use of the versatile units. Besides photography, the light rings gained popularity for microscopic illumination and are widely used in biotech, healthcare and research labs. Forensic and gemology fields use LED ring lights and manufacturers implement the devices for conveniently illuminating individual pieces of machinery.