USING THE ORDINARY CAMERA 187 



with little or no green or yellow near. At such close 

 range as a yard the bellows must be racked out, which 

 diminishes the illumination, so we will call the time 

 two seconds. But the lens should be stopped down. 

 Of the lens which I used, F'jyi was the scale-value 

 wide open. Halving the aperture quadruples the 

 time of exposure. F15 is half of F73/2, so at that 

 stop the time would be eight seconds, and at F30 it 

 would be thirty-two seconds, or half a minute. 



In this case, however, it was almost evening, heav- 

 ily clouded, under trees and bushes, and very dark. 

 So at a rough guess I multiplied the time again by 

 four, making it two minutes, which proved to be 

 just right. Stopping the lens down brought practi- 

 cally all the foliage into focus, as It would not have 

 been at full opening, besides giving more perfect de- 

 tail. When there Is wind and the leaves move, it 

 may be necessary to make some sacrifice of definition 

 and use a larger aperture, not larger, however, than 

 F16. The subject can be shielded somewhat from 

 the breeze by holding a coat to windward, or else we 

 can wait for a lull, or come at a more favorable time. 



Within a few days the eggs hatch, and this Intro- 

 duces us to the work which naturally comes next in 

 order, the photographing of young birds. The 

 young of precocious tribes, as the gallinaclous birds, 

 shore-birds, ducks, and geese, are born clothed and 

 able to run or swim, but those of the ordinary small 

 birds are naked and ugly at first. They grow rap- 

 idly, however, and by about the tenth day are able to 



