The FD-1 is an accessory for use in hand-held macro shooting. It uses cameras' built-in flash for lighting macro shots in dark locations and for photographing moving subjects such as insects. It can also be used for creative shots not achievable by SLRs, such as keeping subjects bright underwater or keeping the background dark for an atmospheric shot. Because the FD-1 is equipped with a light output switching lever, you can adjust the lighting output in approximately 1.4 steps to match the shooting conditions.