Compact magnifying optical system with wide field of view

An optical device, having an optical axis and comprising:

• an objective having a first focal length, which is positive, and comprising a first group of one or more first lenses;
• an eyepiece having a second focal length, which is positive, and comprising a second group of one or more second lenses having a characteristic aberration;
• and
• a power corrector having a third focal length and comprising a third group of one or more third lenses located on the optical axis between the objective and the eyepiece,
• wherein the optical device has an input focal length defined jointly by the first and third focal lengths and a magnification equal to a ratio of the input focal length to the second focal length, and
• wherein the eyepiece and the power corrector together have a combined aberration that is less than the characteristic aberration of the eyepiece.

A method of designing an optical system, comprising:

• (a) selecting, for an objective element group of the optical system, a positive number of objective optical elements;
• (b) defining an objective element group focal length of said objective element group;
• (c) selecting, for an eyepiece element group of the optical system, a positive number of eyepiece optical elements;
• (d) defining an eyepiece element group focal length of said eyepiece element group;
• (e) selecting, for a power corrector element group to be interposed in an optical path from said objective element group to said eyepiece element group, a positive number of power corrector optical elements;
• (f) defining a power corrector element group focal length of said power corrector element group;
• (g) defining a plurality of system requirements for the optical system;
• and
• (h) jointly optimizing respective values of a set of free parameters, of said optical elements, that includes at least one respective free parameter of at least one objective optical element, at least one respective free parameter of at least one eyepiece element, and at least one respective free parameter of at least one power corrector optical element, to satisfy said system requirements.

An optical system comprising:

• (a) an objective for focusing an image of a scene on an intermediate image plane as an intermediate image;
• (b) an eyepiece for magnifying said intermediate image;
• and
• (c) a power corrector for modifying a focal length of said objective while correcting an aberration of said eyepiece;
• wherein each of said objective, said eyepiece and said power corrector has a respective pre-defined focal length.