Last year I picked up a Wanderlust Cameras 11mm Pinwide Pinhole lens. Wanderlust no longer makes this “lens” so it’s a bit hard to find, but I managed to snag one on Ebay for a decent price. Unlike a homemade pinhole lens, which I’ve made and used in the past, the Pinwide is precision milled and 3D printed and creates a much cleaner and sharper image. It has a Micro Four Thirds mount, but I’ve mostly used it on my Sony A7S II with an adapter.