Marion and Co., compiler · London : Marion and Co. · leaf 83
75 PHOTOGEAPHIC OPTICS. of the plate. If it cover only a small portion towards the centre it may be disregarded altogether. … It is almost unnecessary to say that when the subject is such that there are no straight lines, as, for example, in an ordinary landscape, the distortion is not perceptible. Depth of focm. — The beginner, the very first time that he focussed a landscape or other object, will have noticed that…
