- #1
mudicokula
- 2
- 0
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 15 cm projection distance.
I had some luck with ordinary "12x" attachment telephoto lens for iphone and moving the stock projector lens way farther from the DLP matrix than originally inteded and having the telephoto attachment lens right after that. Results were good but projection still bigger than the DLP matrix but focusing was only achieved with a 50cm distance, not closer. I assume the inability to focus at closer distances could also have been from the positioning limits of the focus lens element on the telephoto attachment lens and the stock projector lens.
I guess my first question is what minimum projection angle is possible with DLP projections? I don't suppose it can be made to be the same size or even less than the DLP micromirror array itself for a 15cm throw distance?
Second question, is a telephoto lens the correct approach for achieving this desired result?
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 15 cm projection distance.
I had some luck with ordinary "12x" attachment telephoto lens for iphone and moving the stock projector lens way farther from the DLP matrix than originally inteded and having the telephoto attachment lens right after that. Results were good but projection still bigger than the DLP matrix but focusing was only achieved with a 50cm distance, not closer. I assume the inability to focus at closer distances could also have been from the positioning limits of the focus lens element on the telephoto attachment lens and the stock projector lens.
I guess my first question is what minimum projection angle is possible with DLP projections? I don't suppose it can be made to be the same size or even less than the DLP micromirror array itself for a 15cm throw distance?
Second question, is a telephoto lens the correct approach for achieving this desired result?