A photographic lens is used at f/11 (image-side numerical aperture ) at
PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Fourier optics and image formation · Fourier optics and image formation
What an Instrument Can See, Ch The transfer function of an imaging system
Problem
A photographic lens is used at f/11 (image-side numerical aperture NA≈1/22) at λ=550nm, and carries exactly one wave of defocus, W020=λ. For this amount of defocus this chapter's computed curve crosses zero at ν^≈0.19 of the incoherent cutoff and dips to a minimum of about −0.07 near ν^≈0.27.
((a)) Compute the incoherent cutoff frequency νc, in cycles per millimetre, at the image plane.
((b)) Convert the zero-crossing frequency, 0.19νc, into a bar-target period, in micrometres, at the image plane.
((c)) State what a photograph of a bar target of exactly that period would show, and what a bar target of period corresponding to ν^≈0.27 would show instead.