In a camera (photography), the depth of field/view describes a volume within which objects are acceptably in-focus. Can this behaviour be reversed for a projector to allow the same focal setting to project sharp images on screens at slightly different depths? If so, how (i.e. add more optics to expand the DoF of the projector)?
Of course, it can be. However, in the case od projection there is usually no problem with depth of field. Therefore are lenses for projection more fast.
The DoF depends only on the numerical aperture NA in the image space and on the wavelength λ. A measure for the DoF is the Rayleigh length L_Ray = ½ λ/NA^2 (paraxial approximation). No matter if the image is on a camera sensor or on a projector screen. However, the image space NA of a projector is very small compared to a camera image and the DoF correspndingly larger.
Christof Bodendorf , Peter Zamarovský : As you mention, this is possible in principle. The second part of my question is about achieving this for an existing projector. How would one go about achieving higher DoF for an existing projector? Do you know any resources/links that you can point towards?
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