14 



BIRD STUDIES WITH A CAMERA 



obtained under the same conditions with different 

 lenses. 



Placing a mounted Flicker (Colaptes auratus) on 

 a fence post, and setting up my tripod at a measured 



2. Lens Test No. 1. Mounted Flicker on fence post, distance fifty feet. 

 Eight-inch focus, Zeiss Convertible, No. 10, Series Vila lens; dia- 

 phragm F. 8, VJB second ; Cramer " Crown " plate. Photographed at 

 noon, in sunlight, November 30, 1899. 



distance of fifty feet, a series of test exposures was 

 made, of which three are presented as follows : First, 2 

 eight-inch lens (Zeiss Convertible Series VII a, No. 

 10), stop F. 8, time 5^ second ; second, 4 fourteen-inch 

 front lens of the combination, stop F. 16 (equivalent 



