Okay, I tried it with the problem webcam, HD-3000, exact one as in the original post. Now the brightness was quite low by default in its settings just as explained in the original post, but that was due to the lamp in the background and the way the cam automatically adjusts its internal brightness, so I turned up the "brightness" value in the "configure" settings and it worked fine on my end. It even saved fine and didn't reset or anything like some people were reporting. I'm actually really confused.
EDIT: Also I wanted to apologize for taking months to even look at this issue. I'm a total jerk.