Opteka FL-50AF E-TTL II Dedicated Flash for Canon EOS 50D, 40D, 30D, 20D, 10D, Digital Rebel XT, XTi, XS, XSi, & T1i Digital SLR Cameras Fully Dedicated Guide Number of 22 (ISO 100/m) with Range Up To 10m Flash Ready Indication Auto Detects and Operates, Automatic Shutter Speed Selection Versatile Five Position Bounce Head