Multi-cam video and battery drain

Batteries run out of power, at the worst possible occasion.

A few days ago, I was filming an obedience competition at a local dogs club. I have done this several times before, but only using one video-camera. This time I wanted to use multiple cameras to improve the final result. It's not always so easy to follow the moving dogs with a camcorder on a tripod. Agility is far worse than obedience, but the dogs always moves, sometimes more or less unpredictable.

The three different cameras use for shooting the competition.

The three different cameras use for shooting the competition.

The evening before I charge all batteries and spares for each camera so I did have some time for preparations, even if i got the request to film the day before. The equipment I used was a Sony HDR-CX740 video camcorder, a GoPro Hero Black edition and a Nikon J1 with 10/2.8 fixed lens. Sound with an external Sony microphone mounted on the video camera.

There were four classes and they started outdoor at 9.00 in the morning and continued to 11.30. There were a lunch break and then the next session begun at 12.30 to 15.00. Roughly five hours of filming to begin with.

For the main video camera, a Sony HDR-CX740, I had two large batteries with enough of juice to film everything and then have some spare left if needed. Business as usual.

But with the GoPro was the challenge that the batteries only lasted one hour. This camera housing was attached to a telegraph pole with pink duct-temp. Not so easy to quickly change batteries. There is not an extra charger with the GoPro, so re-charging has to take place in the camera during lunch brake.

Nikon J1 is another story. I hade it mounted on a tripod with a quick-release plate so it was easy to remove it. But, the plate blocked the cover for the battery compartment so I had to remove the plate when changing battery or SD-card. The J1 is a mirror less camera with ability to film, not videocamera. This means the there is a limit of 20 minutes of continuous filming in order to comply with tax-regulations. The consequence is that you can't turn it on and then leave it for two hours even if the battery or SD-card lasts.

So after each participant, I had to run to the Nikon camera and stop filming and then start a new clip. With the GoPro app on the iPhone was it easier to start and stop the GoPro camera remotely. Both methods saved space on the memory cards, but not the batteries.

During lunch break, I copied all footage to the MacBook Pro and re-charged the GoPro camera with the supplied USB-cable and an iPod charger. I forgot to bring with me a charge for the J1 batteries, think that an extra spare would be enough. The extra battery was not an original one, bought in Shanghai just two weeks ago, and didn't have the same capacity as a Nikon one.

Around 13.30 did the last battery in J1 die and there was one to one and a half hour left of the last competition. Fortunately, I had recharged both batteries for the GoPro, so they lasted to the end. 

Some lessons learned from this event are:

  • Use as few types of cameras as possible to minimize the number of different batteries
  • Bring separate chargers for all different types of batteries. 
  • Use original batteries, other may not last as long, especially  when it's cold
  • Use large memory card for fixed cameras, it may not be so easy to switch cards during an event
  • Fixed cams are much easier on a small stage than on a large field where the subject is moving at a distance
  • Don't use a DSLR or mirror-less camera without a camera operator

I'll guess it's time to buy a separate charger for the GoPro and an extra battery pack.

An short video from the event to be found on Vimeo.