aperture opening on the camera increases and as the distance at which 

 the lens is focused decreases. Thus, the depth of field is smallest 

 when a large aperture opening is used when photographing an object 

 very near the camera, and the largest depth of field is obtained when 

 photographing an object a considerable distance from the camera with 

 a small aperture opening. On many cameras a depth of field scale is 

 given in terms of the f-stops and distances available with the camera 

 lens. This scale can be used to determine exactly what portions of 

 the scene to be photographed will be in focus and what portions of the 

 scene to be photc^raphed will be out of focus in the resulting picture. 



Further information on the basic photographic principles can be 

 found in the references listed in the end of this paper. 



Beach Photography 



General . Since pictures are produced by the light reflected from 

 objects in the scene to be photographed, the range of intensities of 

 the reflected light from the scene is important. In scenes which in- 

 clude objects which reflect a narrow range of light intensities, no 

 problem is encountered in properly exposing for all of the objects of 

 the scene. However, in the scenes where a wide range of light inten- 

 sities is produced, care must be taken to properly expose for the most 

 important objects in the scene. When standing at the camera and using 

 a reflected-light-type meter to measure the light on the scene, the 

 light from the total scene is averaged or integrated. Therefore, if 

 there is an especially bright or an especially dull object in the scene, 

 this object will be either overexposed or underexposed if the average 

 or integrated light is used for the whole scene. In beach photography, 

 this principle becomes very important because on sunny days the sandy 

 surface of the beach produces a "beaded screen" effect and light is 

 reflected from the surface of the beach in all directions in relatively 

 large intensities. As an illustration, when such lighting conditions 

 exist, a reflected-light-type meter will measure a larger light intensity 

 when pointed at the sand facing away from the sun than when pointed at 

 the sand facing the sun. Therefore, if the light reading of the general 

 beach is used, objects on the beach will be underexposed and appear as 

 silhouettes (see Figure 1). This picture was made by using the light 

 meter as shown in Figure 2 to take a reflected light reading of the 

 dry surface of the sand. Notice in Figure 2 that the light cell was 

 pointed slightly downward so that the reflections from the sand were 

 measured rather than the brightness of the sky. The use of a light 

 meter to obtain proper exposure for figures or structures on the beach 

 is shown in Figure 3. Here the meter is pointed directly at the person 

 to be photographed and is held relatively close to the person to exclude 

 reflected light from the surrounding sand areas. When the meter is used 

 in this way the persons on the beach will be properly exposed but the 

 background beach area will be overexposed as illustrated in Figure 3. 



