Due to quantum physics, there's actually only two degrees of freedom in the ways light can be polarized, referred to as the "Jones Vector". In other words, it's impossible even in theory to distinguish between light that has exactly two perpendicular polarizations mixed together and light that is fully unpolarized and has thousands located all around the circle. That makes it surprisingly possible to build a camera that captures _everything_ there is to know about light at some particular frequency.
Not quite — that’s for polarized light. For general light that may be unpolarized, you need four parameters. You can use the Stokes parameters, or, if you’re feeling very quantum, you can describe the full polarization state of a photon by a 2x2 density matrix. (I have never personally calculated this, but I’m pretty sure you can straightforwardly translate one formulation to the other — the density matrix captures the polarization distribution of a photon sampled, by whatever means, from any source of incoming light.)
https://en.wikipedia.org/wiki/Jones_calculus