PHOTOGRAPHY AND PHOTOMICROGRAPHY. I3I 
obtained from Bausch & Lomb, who are under contract to manufacture them 
according to the Zeiss formule. In buying a photographic outfit it is economy to 
get one of the high-priced lenses. It is frequently stated, by those who do not 
know, that “just as good results” can be obtained with cheap lenses, but one may 
easily satisfy himself that such is not the case by photographing buildings on a 
Fig. 121.* 
street or any object having many vertical parallel lines and other lines crossing at 
right angles. The pictures made by the cheap lenses generally show serious distor- 
tions. In buying a lens one should know in advance exactly what he wishes to do 
with it, otherwise he may be greatly disappointed. If he wishes to photograph only 
*Fic. 121.—Newer form of Zeiss-Abbe drawing camera. The camera is clamped at K by means 
of S. The prism within R is centered over the eye-piece by screw movements of L, and Z. When 
not in use the prism is swung to the right, as indicated by the dotted lines. The mirror A. throws 
down the prismatic image to the drawing paper. The amount of light is governed by the substage 
iris-diaphragm and by rotating B and R, which contain smoky glasses of graded densities. P is 
an extra prism, The image on the paper will also be clearer if it is placed in shadow by means of 
a screen of some sort. 
