Last week we were filming the second video ever using our new GH5s, and one of the cameras ran out of batteries in the middle of a take. At the time, we didn't think anything of it and we simply replaced the battery and continued filming. When we transferred all of the footage after the shoot, one of the video clips was corrupt and we had to re-film the entire project.
When this first happened, I thought there was something wrong with our cameras, but I then remembered that we'd had our GH5s die before without ever losing any footage. I then discovered that the issue wasn't with the camera, it was with the cheapo third-party battery that I had purchased online.
When a camera battery is about to die, the camera needs to accurately determine how much charge is left. When the battery is working properly, the GH5 will shut itself down before the battery completely dies. The "Dot 1" battery that we were using wasn't correctly communicating with the camera, and instead of giving us a warning beep and shutting down, the GH5 would instantly turn off without properly shutting down and saving footage.
I then decided to put all four of my batteries to the test. Surprisingly, the best-performing battery was not the genuine Panasonic DMW-BLF19. The best-performing battery was actually the "Newmowa" version. These batteries are currently being sold on Amazon, and you get two batteries and a dual charger for just $27. The Panasonic version is $55 for a single battery.
In the past, I've had a very good experience buying third-party batteries for our Nikon cameras, and from what I can tell, these Newmowa batteries seem to be reliable as well. If we ever run into any issues with them, we will immediately update this post.
Of course the safest thing to do would be to stay away from third-party batteries altogether. One Fstoppers reader just sent me this great article that talks about staying away from third-party batteries with the GH4.