Probably the second most important task of picking the right camera and lens kit for your next project is choosing the right power solution for your primary capture device carefully. Whether you decided to shoot with a high-end professional digital camera such as the ARRI Alexa or RED Epic or with a less expensive and much more affordable one like the A7s or GH4 for instance, you’ll definitely need a power supply, especially if you are planning to spend more than 8 hours on set on a daily basis.
Atomos recently announced a hot-swappable power solution for popular cameras like the GH4, A7s, 5D Mark III they call the Power Station, which we covered here. An external battery solutions might also be beneficial for your additional rig accessories such a monitors, audio preamps/recorders, remote follow focus systems, shotgun mics, etc. A couple of the tiny batteries that come with your GH4 or A7s probably will give you enough power for a couple of hours while shooting in the wild. However, they can’t be considered as a reliable power solution for a professional set in most of the time.
Caleb Pike from DSLR Video Shooter explores some of the viable options on the market today considering the most efficient and reliable external battery pack. The one that he picked was the Switronix Powerbase 70 battery pack.
The Switronix PB70B Battery Pack is a 70wh 14.8v lithium-ion battery pack that offers up to 6x the runtime of the smaller kit batteries of your camera. It is equipped with a 1/4-20 threads that allow you to mount accessories on either side.
The beauty of the PB70B is that it can provide enough power for your camera and maintain up to 2 additional 12 VDC devices as well, It can also support devices that require low voltage via the XP power regulation cable. The other thing that separates the PB70 from the cheaper external power solutions on the market is that it has a dedicated LED indicator that will give you a very good idea how long the current charge of the battery pack would last. This will help you to avoid possible damage to your camera system due to lower voltage supply.
In addition, as Caleb suggests, along with the PB70 Battery Pack, you can use a V-mount Plate. Both can be easily mounted on the rear side of your camera rig, thus giving you good balance on your camera set up and enough power for you devices as well.
The V-Mount system definitely deserves consideration as it gives you a plenty of options that could be quite beneficial for you while operating with your camera on a regular 12-14 hours shooting day. His tests show that the PB70 Battery Pack could provide enough power for the GH4 for at least two full shooting days with a single charge only. You can attach the battery pack under your camera or to your V-Mount Plate. There are plenty of adaptors, cables and other add-ons that can be adapted to your preferable camera system and additional devices.