Recycling time with 4 fresh AA alkaline or NiMH batteries in the flash itself
NiMH times and flash counts are similar to alkaline batteries
External Power Supply CP-E4
Remove the contact cover from the side of the flash. Then connect the power cord for the CP-E4 to the flash. This power the is used to recycle the flash faster so be sure to have batteries in the flash as well.
Now you can go to Custom Function 7 on the flash and set this function to use either the external power source only or the external and batteries to recycle the flash.
Approximately 350~2450 exposure and a recycle time of 0.1~2.0 seconds with alkaline batteries
Approximately 400~2800 exposure and a recycle time of 0.1~1.5 seconds with Ni-MH batteries