46 NATURE AND THE CAMERA 



tered. Apart from what we might term the natural 

 difficulties, such as the stalking of the bird and get- 

 ting the camera within suitable range, there is the 

 question of light, for usually instantaneous exposures 

 are necessary. Now we all know that most birds 

 build their nests in shaded places, places chosen with- 

 out the slightest regard to the needs of the bird pho- 

 tographer, and in these shaded places an instantane- 

 ous photograph is practically an impossibility. Then 

 there is another difficulty, one even more serious : 

 In close-range work the depth of focus of an open 

 lens is very slight. Objects to be in sharp focus at a 

 distance of a few feet must be nearly on one plane ; 

 three or four inches one way or another will make 

 a very great difference in the definition. Now sup- 

 pose you focus the lens on the near edge of the nest, 

 so as to secure a sharp picture of the young birds 

 when they raise their heads ; then the mother bird 

 comes and perches either on the farther edge of the 

 nest or on a twig several inches beyond. Under 

 such conditions you may not stop down your lens in 

 order to increase its depth of focus, owing to the 

 lack of light, so you have to sacrifice the sharpness 

 of either the old bird or the young. The method 

 adopted by some bird photographers is to insure the 

 correct lighting by removing the nest from its natural 

 position and placing it where conditions are favour- 

 able for photographing. This method is not to be 



