imaging non-monochrome lenses are complicated, projector and camera lenses can have 6-8 or more elements. Sadly you can't just put one lens element to focus the projection beam to infinity.
I have a very very unusual project requirement where I need a pocket video projection with the lowest possible projection angle or "longest possible throw-ratio".
It's a pocket DLP projector so goal is to have the beam remain ,as much as possible, almost the same size as the DLP matrix, for a...