26 NATURE AND THE CAMERA 



easy to obtain a really satisfactory photograph of this 

 nest. If we expose for the interior, the exterior suf- 

 fers, and vice versa. To hit upon the happy medium 

 requires both care and experience. After trying vari- 

 ous methods, I have found the most satisfactory thing 

 to do is to throw a ray of sunlight into the nest by 

 means of a mirror. This light should be allowed 

 to enter the nest only during a small part of the 

 time necessary for the exposure. For example, sup- 

 posing your lens to be cut down to a very small 

 aperture, when the correct exposure would be perhaps 

 forty seconds ; then while the lens is open and the 

 exposure taking place, allow the sunlight, reflected 

 from the mirror, to illuminate the interior of the nest 

 from two to six seconds. Too much local illumina- 

 tion destroys the effect of the depth of the nest and 

 is therefore to be avoided. While using the mirror, 

 keep it in constant motion, so that the light will be 

 diffused. 



When photographing ground nests in open, wind- 

 swept fields, it will sometimes be found necessary to 

 place a cloth screen around the nest (far enough 

 away not to interfere with the picture) to protect it 

 from the wind. Otherwise only a very short expo- 

 sure can be given. 



NESTS IN BUSHES AND TREES. Here we come to 

 the most satisfactory nests from a photographic stand- 



