I absolutely suggest looking into the Samyang AF 12mm f/2.0 E for your FX30! It is such a fantastic choice because it hits that sweet spot between the 11mm and 16mm you mentioned. While the Sony 11mm can get a bit wild with the barrel distortion, this Samyang lens is incredibly well-behaved for architectural lines and studio walls. It is a very safe and reliable piece of glass that I trust completely for professional work. The best part is definitely the price point! You can usually find it brand new for well under $400, which leaves you extra cash for lighting or sound gear. It is amazing how sharp the image stays even when shooting wide open at f/2.0. If youre worried about those tight NYC spaces, the 12mm focal length provides a much wider field of view than the Sigma 16mm without looking like a GoPro. Truly a solid investment for the money... definitely worth a look!

ngl I have been really happy with the Viltrox AF 13mm f/1.4 STM Sony E-Mount lately. It handles those tight studio shots perfectly without making faces look too distorted like the ultra-wide stuff does. I've used it on several FX30 gigs and it works well every time. It fits right under your budget too... let me know if you need more tips for that setup!