I use a Wollensak (= Beseler?) 18" f5 (approx) opaque projector lens on my 8x10 camera. The lens is a Cooke triplet and it "illuminates" 11x14 with plenty to spare. At full aperture the challenge is field curvature which means soft corners on 8x10 and seriously soft corners on 11x14. Central image quality is brilliant and contrasty but film sharpness is hampered a bit by a hint of secondary chromatic abberation. This would not have been a problem on an opaque projector.