I want to be able to set the focus at far distances, like 500 m, but in a smaller setting, like 5 m. What lens could I use to achieve this?
I have found this lens that achieves it for a FOV of 120 degrees. But it lacks info (e.g. ray tracing, lens info) on how it's done. I work with FOV like 60 and 30 degrees. I have no settings on the lens, just manual screwing in or out.
To be clear, as an example. I was to set the focus for 500 m while inside a room 5 m wide, using lens to give the equivalent focus. So I can go outside later and the focus will be set at 500 m without additional lens.