Filters are definitely relevant for astro. I've imaged the sun with a 20 stop ND in front of the EF-RF adapter variable ND.
Generally though filters are more relevant for astro at telephoto lengths than UWA. Still I felt the same as you did on the 11-24 about adapting the Sigmas partly for that reason.
Generally though filters are more relevant for astro at telephoto lengths than UWA. Still I felt the same as you did on the 11-24 about adapting the Sigmas partly for that reason.