TAKING PICTURES 



129 



when the object is in focus ; meanwhile he moves the lens 

 or the back of the camera back and forth by means of a 

 screw, till the image on the glass shows distinctly. This 

 image is inverted. 



Rising and sliding front. As an aid in focusing, some 

 cameras have a rising and sliding front. By means of a 

 screw and a lever the lens may be moved either up or down, 

 or from side to side. This enables one to easily cover the 

 portion of the object that is to be included in the picture, by 

 simply moving the lens, 

 instead of moving the 

 whole camera as would 

 otherwise be necessary. 



In the other method 

 of focusing, the camera 

 is tested before leaving 

 the factory, and the po- 

 sitions at which an object 

 will be in focus for certain 

 distances are marked on 

 the camera. The person 

 estimates the distance of 

 the object and sets the 

 lens accordingly. When 

 this method of focusing is used, there is attached to the 

 camera a finder, in which appear the objects that will show 

 in the picture. In the box type of kodaks, there is no focus- 

 ing arrangement, as the camera is made so that any object, 

 within ordinary limits, will be fairly well focused. 



Setting the diaphragm and the shutter. After the camera is 

 focused, the next steps are to set the diaphragm for the size 

 of the hole, and the shutter for the time of exposure. These 

 depend on several factors, such as the nature of the object 

 being taken, the kind of day, and the time of day. The 

 time of exposure also depends on the size of the diaphragm. 



FIG. 42. Box camera. 



