A simple sensor is protected by a circular baffle (diameter ) mounted in front of an…
PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Geometrical optics and imaging · Geometrical optics and imaging
What an Instrument Can See, Ch Pupils: the aperture of a linear system
Problem
A simple sensor is protected by a circular baffle (diameter 20 mm) mounted 400 mm in front of an axial object point O. A further 200 mm behind the baffle sits a thin objective lens of focal length 50 mm and diameter 12 mm, which forms a real image of O. No other apertures are present.
((a)) By computing the half-angle each aperture subtends at O, identify which of the baffle and the lens rim is the system's aperture stop, and state the diameter and position of the entrance pupil.
((b)) Compute the object-side numerical aperture and the corresponding object-side f-number of the system.