OPTICAL SYSTEM FURNISHED WITH A DEVICE FOR INCREASING ITS DEPTH OF FIELD

摘要

To increase the depth of field of an optical system, an inversion of chromatism is carried out. Account is taken of the fact that, in natural light, for their photographs, users favour long-distance snapshots, outdoors, where the illuminant is composed rather more of blue, and short-distance snapshots, indoors, where the illuminant is composed rather more of red. Whereas optical devices naturally focus the blue components at a shorter distance than the red components, which is then unfavourable, with the inversion of chromatism, a focusing which is more suited to requirements is re-established.