Here we take a quick look at the Canon CP-E4 external battery pack for the Speedlite 580EX and
580EX II Speedlite
shoe mount flash units. The pack also works with the Canon 550EX, 540EZ, 430EZ, MT-24EX and MR-14EX flashes. This unit is an inexpensive alternative to the high voltage turbo packs that can cost many times what this battery pack costs making this ideal for low budget shooter. It's also nicely sized to be worn on your belt if you happen to be wearing one. You lady photographers may need to attach this pack to the bottom of your camera or carry it in some other way if you're not wearing a belt.



The CP-E4 is the next generation of the also available
Compact Battery Pack CP-E3 for 580EX, 550EX, 540EZ, 430EZ, MT-24EX and MR-14EX Flash Units
from Canon. The performance in terms of recycle times with the 580EX flash is identical but the new CP-E4 adds weather sealing to the list of features it comes with making it the best choice for use with 1D series bodies and the new weather sealed
580EX II
flash. A new seal is added on both the AA battery holder and the connection to the flash unit.



Performance from this external power source is quite good considering the asking price from retailer of right around $150. Recycle time with the 580EX from a full power blast are consistently at 2 seconds, while without they are closer to 2.5 seconds. The big draw to use this unit is that you are now pulling power from 12AA battery cells rather than only four. This means that you have three times the available power, making for significantly longer use between battery changes. I've found that I can shoot an entire event with 600-1000 flash shots with just one set of NiMH rechargeable batteries between the flash and CP-E4 pack giving me the confidence to shoot for a long period with the worry of my flash batteries going dead. Equipped with my Canon EOS 5D with the BG-E4 battery grip and two 511 batteries, one 580EX and the CP-E4 I can confidently shoot with flash all day or night.



One additional benefit I find is that you are not putting the full load of supplying energy to the flash unit from the four internal AA cells alone but rather from 12 cells with eight of them being located outside the flash. The big benefit to this is that you are not building nearly as much heat inside the flash unit which helps to keep the flash unit from melting down from excess heat.