I did a search, but couldn't find what I was looking for, basically a list of wide angle primes (less than or equal to 24mm) I can check out.
I chose primes because it's smaller for travel.
I want to use it on a full frame camera, so I don't want a APS-C lens.
Autofocus is not essential, I don't mind using an old lens with adaptor, manual focus with stop-down metering. (ie. mount doesn't matter, so long as I can get an adaptor)
I want something with good image quality.
Say.... a budget of $400, what's available?