Dual Focus

[Rev. Green]

Is it possible to make a compound camera lens, perhaps using materials like Iceland Spar, which could simultaneously focus comparatively well on two objects, one near, one far, while leaving the middle distance blurred?

[Buenchico]

I've been trying to work out the physics of that and, as far as using a single lens is concerned, I can't see how it could work. One might try using two separate lenses, with a common focal plane, but, in these days of computer technologies, it would seem simpler to me to use two entirely separate optical systems (with one using a near focus and the other using a distant one) and then combine the images together electronically.

[Jonathan-Joe]

Would it possible with a lens whose centre has a short focal length with a concentric outer based on a lens with longer focal length? Though some of the field would appear in the image twice, once clear, once out of focus.