I’d say go with the Sony F

I’d say go with the Sony FX1 for better low-light response over the FX7, which uses a different type of sensor. I’ve used the FX1 for everything including stage plays, and it works well under a wide range of conditions. But keep in mind that a better camera may not solve all your image quality issues – you’ll still need to work on shot composition, audio quality, editing, etc. For audio on the FX1 you can add an XLR adapter if necessary.