Thanks for checking the camera. I'm sure it's in auto mode with standard settings. I'm somewhat of a camera buff, so I understand how to set it up. Unfortunately, the settings I need to use to correct this issue won't stick in Auto mode. It'd be nice if there was some kind of "program" mode that let you setup things like ISO, exposure, AWB and have the settings persist between uses. But that does not exist for the S4 stock camera.
It'll be a few days before we see any sun, according to the weather guessers around here. I was testing it quite a bit today in heavy cloud cover and it worked pretty well, about what I'd expect of it. I'll test it again the next time we get some sun, but am not confident it is going to fix itself.
I'm testing some other camera apps. Camera 360 is decent, but no video mode. So not an "all in one" solution.