Now let's talk about how much time you can record with the 64GB SD card. It depends on your camera settings. YOLOtek recommends 1080p/60fps. Good resolution and you can do a little slow motion in editing and give you about 4 hours record time.
RESOLUTION... little p or k
1080p is the resolution. Lots of folks talk about 4k but the file size is much bigger and most folks don't see much difference while viewing on mobile. If you are using Looping and only saving the good video, you might try 2.7k/60.
FRAME RATE... or FPS (frames per second)
30fps or 30 frames per second is the standard rate. We prefer 60fps, so that when the fish jumps or some other action happens that you want to slow down (slomo / slow motion), you can slow it down in editing.
Times from GoPro Hero 5 Black
64gb at 1080p/60fps = approx. 3hrs59min
64gb at 720p/30fps = approx. 5hrs43min (This is just to see the longest time on the SD card. We would still recommend 1080p/60fps)
64gb at 2.7kp/30fps = approx. 2hrs44min
64gb at 2.7kp/60fps = approx. 2hrs05min (save as 4k/30fps, but higher frame rate for better slomo)
64gb at 4k/30fps = approx. 2hrs05min (H5B only does 30fps on 4k)