A high relative aperture objective lens system with compound focusing

摘要

A high relative aperture objective lens system with a compound focusing system, comprising four lens components of varying respective distances, in which the first component is of positive refractive power, the second component is of positive refractive power, the third component is of negative refractive power and the fourth component is of positive refractive power.;The said lens being designed so that focusing is produced by translating the said second and fourth components, the aberrations-and notably coma-being well corrected throughout the whole focusing distance range.