CHAPTER XIII 



CAMERAS AND PICTURE-MAKING 



But who can paint like Nature! JAMES THOMSON, The Seasons 



The pinhole camera described in the preceding chapter is 

 seldom used because it takes so long to expose the plate that any 

 moving object produces only a blur. A lens with a large opening 

 that admits plenty of light is used in place of the pinhole, and 

 this lens forms an image on the sensitive plate or film. A camera, 

 then, is a light-tight box 

 with a lens at the center 

 of one end and a device 

 for holding a sensitive 

 plate or film at the oppo- 

 site end. The interior 

 of the box is painted 

 dull black to absorb any 

 possible reflections from 

 the metal mounting of 

 the lens. 



In all box cameras 

 (Fig. 156), such as the 

 familiar Brownie No. i 

 or No. 2, the lens must 

 be what is known as a universal lens; that is, one which will 

 give a reasonably distinct image of objects on the plate or film 

 no matter whether they are distant or quite near. Such a lens 

 cannot take a picture of a very close object, however. In the 

 Brownie the near limit is 6 feet. 



In all other cameras, the lens is mounted on a movable board 

 which is connected with the front of the camera box by a bellows. 



309 



FIG. 156. A box camera, the Brownie 



