The software in windows is terrible for logitech. On mac there are third party software that lets you adjust literally everything. And doing so I can make the C920 look just as good as my iPhone especially in good lightning.
Can you share the third-party software you are using? I hate my C920 right now. I'm already pale, and it makes me look on the edge of death in every call.
I've seen people share config software for these on Windows but haven't seen anything that looks decent for Mac use.