Check out the Schmidt camera to see what little glass can give you great optical performance if you can live with a curved image plane. The Baker-Nunn camera pu

Check out the Schmidt camera to see what little glass can give you great optical performance if you can live with a curved image plane. The Baker-Nunn camera puts this to the extreme: 500mm, f/1, 30 degree FOV. Even a simple Schmidt–Väisälä in 400mm f/2 can cover a 4000px wide sensor with 5.5 micrometer pixel size perfectly (even 3.5 micrometer pixels would still be useful, especially if color).