Nikon SB-20 Speedlight Electronic Camera Flash Angle of coverage: 45 horizontal and 60 vertical; with zoom head set at N, tilting flash head provides -7 to 90 adjustment Automatic TTL flash output control with Nikon AF SLR cameras with AF assisted control. For other Nikon SLR with ISO-type accessory shoe such as F301, FA, FE2, or FG; automatic exposure control with any Nikon SLR (with Flash Unit Coupler AS-4. AS-7 or AS-17 required with Nikon F3). TTL Balance filled-flash possible with capable Nikon AF bodies. Manual control: choose from full, 1/2 1/4 1/8 and 1/16 output Guide number (ASA/ISO 100 In feet) 100 with zoom head set at N ASA/ISO film speed range: ASA/ISO 25-1600 Recycling time: Approx. 6-7 sec