Not necessarily. The Epson LS800 comes with a screen included, so you won’t need to buy one yourself. For screen-free installations, the Optoma CinemaX D2 is a top choice, with Wall Color Adjustment and the ability to project on angled surfaces, and the Optoma UHZ50 can also be used on curved or slanted surfaces with no issues. For the rest, a screen will ensure the best image quality, though you can project straight onto a wall as long as you have a flat, white surface that’s large enough.