E-TTL autoflash offers natural looking, fully automatic close-ups with flash. Equipped with twin flash tubes, enabling 3-dimensional flash photography by controlling shadow varying the flash ratio of each tube from 1:8 to 8:1. Supported by the EOS-1V, the EOS-3 and other E-TTL supported cameras. High-speed sync (FP flash), FE lock, FEB, Wireless Autoflash, first and second-curtain sync and 7 custom functions. Guide No. 14/46 in m/ft (at ISO 100), closest coupling range is approx. 20mm/0.8 in. from flash head. Equipped with two small lamps for focusing in low-light conditions, flash exposure confrimation lamp. Can be mounted directly to EF 50mm F2.5 Compact Macro, EF 100mm F2.8 Macro USM, EF 100mm F2.8 Macro and MP-E 65mm F2.8 1-5X. Requires optional Macrolite adapter 72C to combine with EF 180mm F3.5 L USM Macro. Power source: 4 AA-size batteries. Equipped with terminal for external power source. Weight: 15.1oz.