This O-Flash Macro Flash unit is a unique adapter for your hot-shoe flash unit designed to replicate the lighting effect produced by traditional, expensive, and heavy powered studio ring flash units. The most best tools for macro photography. And it is portable and lightweight, has been designed to take advantage of a camera's TTL metering capabilities. Because this flash relies on the hot-shoe flash to generate its light, it contains no electronics, no flash tubes and requires no cumbersome cables. The light distribution is accomplished through a sophisticated system of internal prisms, reflectors and light-shapers designed to distribute and project the light evenly around the lens. This Flash allows infrared AF assist beam pass through the flash ring. TTL functions will work normally when using this O-Flash. As with standard flash use, manual exposure control requires the use of a light meter or test-shots.