The Sigma EM-140 DG Macro Flash is ideal for photographing subjects in fine detail and is extremely effective for scientific and medical applications. Dual flash tubes can fire simultaneously or separately. Using only one flashtube creates modeling, which can give a three-dimensional feeling to the subject. The flash features a guide number of 14 w/ISO 100. The Modeling Flash function makes it possible to check for reflections and shadows before actually taking the flash picture. A wireless flash function is also available, where the EM-140 DG is used as master and the EF-500 DG SUPER as a slave unit for creating fine shadow details. 55mm and 62mm adapter rings are included with the flash. 52mm, 62mm, 67mm, 72mm and 77mm adapters are sold separately.