It's not cuz you upgraded the camera, it's because dev has locked relationship progress behind certain interactions at rel level 20 and 40.
You've hit the cap at the same time you upgraded the camera, hence the coincidence and you need to do something in order to progress further.
Before you start the night, when talking with the girl, you'll have an option to chat with her - she'll give you a hint, what you need to do next.
Hope this answers,
Cheers