Abstract: The present invention provides a complex modular afocal variator in which a modular afocal variator is supplemented with additional optics to form a more complex, but still modular afocal variator system, that can impart internal focusing as well as active spherical and chromatic aberration corrective improvement.

Abstract: The present invention provides optical systems containing an afocal variator able to impart focus means to the optical system, as well as essentially constant magnification throughout the focal translation. The present application teaches a specific formula or set of spacing requirements for the positioning of the afocal variator that can be used with any afocal variator optical lens system comprised of various lens combinations. Provided that the formula for spacing the afocal variator within the optical system is utilized, the afocal variator acts not only to focus the optical system but maintains substantially constant magnification during the translation of focus.

Abstract: The combination in optical series of a microscope objective lens system with a first positive lens system, and a focusing module, all in combination with one another and with such other components as are required to provide a microscope image, allows the user of such a microscope, to continuously alter the active focal relationships of the microscope by continuously varying the afocal variator and the distance of the microscope objective lens system from the object which is undergoing examination, and all without the need to physically change the length dimension of the microscope system, and without the need to change the positions of any of the lenses outside of the afocal variator, and without the need to change the microscope objective lens. The focusing module includes, a front negative lens system, an afocal variator optical system, and a rear positive optical system. The afocal variator optical system includes in optical series a front positive lens, a negative lens, and a rear positive lens.