Tessor type lens systems for facsimile

A tessor type lens system comprising a first positive meniscus lens element, a second biconcave lens element and a third cemented doublet element consisting of a negative lens element and positive lens element, said lens system having the following numerical data:

• ______________________________________ .gamma..sup. = .infin. d.sup. = 13.158 n.sup. = 1.51633 .nu..sup. = 64.1 .gamma..sup.1 = .infin. d.sup.1 = 1039.145 .gamma..sub.1 = 39.474 d.sub.1 = 9.211 n.sub.1 = 1.77250 .nu..sub.1 = 49.6 .gamma..sub.2 = 394.832 d.sub.2 = 6.711 .gamma..sub.3 = -97.368 d.sub.3 = 5.395 n.sub.2 = 1.71736 .nu..sub.2 = 29.5 .gamma..sub.4 = 34.697 d.sub.4 = 7.369 .gamma..sub.5 = -788.105 d.sub.5 = 2.632 n.sub.3 = 1.58144 .nu..sub.3 = 40.7 .gamma..sub.6 = 47.368 d.sub.6 = 8.158 n.sub.4 = 1.83481 .nu..sub.4 = 42.7 .gamma..sub.7 = -66.426 d.sub.7 = 84.174 .gamma..sub.8 = .infin. d.sub.8 = 1.316 n.sub.5 = 1.77250 .nu..sub.5 = 49.6 .gamma..sub.9 = .infin. f = 100, F/4.5 ______________________________________
• wherein:
• .gamma..sub.i represents the radius of curvature of the i-th refractive surface counted from the object side;
• d.sub.i represents the i-th axial distance (i.e., airspace or lens thickness) counted from the object side;
• n.sub.i represents the refractive index with respect to d-line of the i-th glass material counted from the object side;
• .nu..sub.i represents the Abbe number of the i-th glass material counted from the object side;
• f represents the focal length of the whole lens system.