An introduction to the science & practice of photography (1891)
Jones, H. Chapman (Henry Chapman), 1854- · London : Iliffe & Son · leaf 91
mpinge upon its sur- face will be transmitted as a pencil of parallel rays. It does not at all follow from this fact that an unsymmetrical lens (plano-convex, convex meniscus) will produce the same effect with either side towards a luminous object ; indeed, if such were the case, it would be… … Fig. 14 lens as the principal focal point, the point of light pro- duced on the other side of the lens, will be at exactly the same distance from the lens. Any such pair of points are called " conjugate foci." Any number of luminous points will be simultaneously reproduced by the lens, and there-…
Photography
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