Scan angle doubling lens

[Pangolin]

speaking of lenses, a cool projector add-on would be a 'lens' with zero power on the top half and negative(diverging) power on the bottom half for crowd scanning. Could be made simply by polishing a depression (or depressions) out of the bottom half of a glass hemisphere. The diverging bottom half could be for crowd scanning, yet the beams out of the top half would remain relatively untouched. And it's pretty fail-safe - no electronics

What you're talking about is called a "split diopter". I have talked about this many times over the years and have even used it a few times. Sounds good on paper, but as the beam crosses the split, distortion and dispersion does occur.

I haven't talked much about split diopters lately because we have a better idea now .

Bill

[mixedgas]

For the record, the lens we used to shoot that picture is NOT a 2x Galilean telescope set to infinity with the scanners placed at the crossover point. Its very much more sophisticated then that, with a field flattening element in it, or Garfield would be fuzzy at the edges. Instead Garfield is in focus or near focus all the way from the lens to the wall.

That is a 7 element lens with one external element added and Garfield is NOT geocorrected in software......



Steve