6 NATURE AND THE CAMERA 



back is not always understood by the beginner : its 

 object is to enable him to bring both foreground 

 and distance in focus. This is particularly noticeable 

 when the subject in hand is a birds' nest or some such 

 object on the ground, and you have to place the 

 camera low down. The part of the foreground near- 

 est the lens is so very near, while the distance is so 

 much farther off, that, to have the whole picture in 

 even fairly sharp focus, you would have to use the 

 smallest diaphragm, and consequently a very long 

 exposure would be needed. By using the swing- 

 back, swinging the upper part back and the lower 

 part forward, you can to a limited extent obviate this. 

 Remember that the nearer the object is to the lens 

 the greater must be the distance between the lens and 

 the plate, and vice versa; and as the back swings, so 

 does it increase or decrease the distance between the 

 lens and the plate. 



In the matter of lenses there are several important 

 things for the nature photographer to bear in mind. 

 Speed is absolutely necessary in most branches of 

 work; depth of focus also is necessary ; perfect defini- 

 tion and covering power are equally important. To 

 insure covering power it is advisable to have a lens 

 whose covering capacity is at least one inch greater 

 than the largest plate you intend to use. Then if you 

 use the rising and falling front you can use it without 

 sacrificing definition at the upper or lower end of the 



