VARIABLE FOCAL OBJECTIVE FOLLOWING LARGE REPORTS COMPRISING ASPHERIC SURFACES

摘要

P The objective comprises moving groups and at least one fixed lens group, in at least two of which groups is inserted an aspherical surface. The mobile groups consist of simple lenses, at least one of which has an aspherical surface, the fixed group (s) possibly comprising on their side at least one aspherical surface. The fixity of the image plane is provided by mechanical compensation for focal length variations of greater than five and easily reaching eight. Aspherical lenses are arranged so that, for the same zooming, the total number of lenses of the objective, spherical or not, is smaller than in any other lens with variable focal length and still image plane, comprising only spherical lenses. BR/ This results in a mass lightening of the lens, including moving parts, and a reduction in the energy required to move them. BR/ Application: color television camera. BR/ (CF DRAWING IN BOPI) BR/ BR/ / P