One of the selling points for the YN565EX is that it can be used with an external power supply. As shown above, the standard Canon three prong power connection is next to the old style “PC” flash connection and protected by a rubber cover. As reported previously, I have a Pixel TD-381 external battery pack; I wanted to see how well it worked with the YN565EX flash.
As expected, the TD-381 simply plugged right into the YN565EX and worked fine. My TD-381 is fitted with NiMh batteries. I recharged the batteries and made a few simple recycle time tests with the YN565EX.
A few years ago I began to use the XNote Timer as a stopwatch to get approximate timing for shutter lag, flash recycle, etc. I again photographed the XNote Timer to get an idea of the recycle time for the YN565EX with and without the TD-381 power pack.
With four freshly recharged NiMh batteries, the YN565 can get off five full power flashes in about 10.7 seconds. When powered by the TD-381, recycle time is reduced such that five flashes can be done in about 6 seconds. As reported previously, the YN565EX recycles somewhat faster than the Canon 580EXII when both are powered by internal batteries; however, when connected to the TD-381 power pack, the recycle time is about the same.
On a somewhat related note, I used the YN565EX as a slave flash driven by the 580EX II mounted on a Canon 7D camera over the Thanksgiving Holidays. It worked well.