Sigma EF-630 Electronic Flash for SigmaThe Sigma Electronic Flash EF 630 is a multifunctional clip on type flash, which offers a greater output of light with a guide number 63. Among the diverse features loaded on this flash is TTL exposure control as standard as well as high speed sync, rear curtain sync, and wireless flash functions. The Auto zoom function which is designed to work with focal lengths 24 200mm, bounce flash function, Wide Panel, and Catch light Panel of the EF 630 are