Pioneer DC500 - Manual (Page 35)

EN-35
Using the Sea or Ext. Flash Modes
These two scene modes are special exposure programs developed for taking pictures underwater.
Sea Mode - Select this mode to take underwater photos without external flash accessory
(optional). This exposure program was developed by scuba divers and will
produce the best quality underwater images when NOT using the external
flash (optional).
Ext Flash Mode - Select this mode to take underwater photos with external flash accessory
(optional). This proprietary exposure program synchronizes the camera's
flash and exposure controls with SeaLife External Flash (SL960) or Digital
Flash (SL960D). It has taken over four years of underwater research
For bright and colorful underwater pictures, we highly recommend purchasing the optional SeaLife External
Flash (SL960) or Digital Flash (SL960D).
The Sea or Ext Flash mode setting will be preserved even after the cameras power is turned off, so don’t
forget to change back to the Auto scene mode after underwater use.
The inner camera is not waterproof. Seal the camera inside the waterproof housing for use in and around
water.
and testing to develop this program.