170 HOW TO STUDY BIRDS 



lens and fixed focus, or those which do not allow of 

 focusing upon a ground glass and require one to 

 measure or guess at the distance are almost worthless 

 for this purpose. Occasionally one might happen to 

 secure a good picture, but it is a heavy handicap. It 

 is hard sometimes to have to inform an inquirer that 

 his much-advertised affair will not fill the bill. Nor 

 is the particular " make " important, so long as it is 

 of a type adapted to do the work. 



There are two types of cameras necessary for the 

 fullest success in this work, for different classes of 

 subjects first, for general purposes, the ordinary 

 long-focus instrument, and then, for certain special 

 work, the reflecting type of camera. The beginner 

 should first secure the former and learn to use it. 

 Then, if he or she wishes to go farther, the other 

 may be acquired. 



The best all-around instrument for general pur- 

 poses is some well-made focusing camera using the 

 4x5 inch size of plate, of light weight, with not less 

 than sixteen inches front " draw " from plate to lens, 

 preferably a little more. This length of bellows will 

 allow the use of single lenses of the doublet, or of a 

 telephoto attachment. Instruments that have back 

 draw have longer bellows, but are heavier than is 

 necessary. The lightly-built " cycle " models answer 

 every purpose, and the matter of even a pound or two 

 is important when it comes to all-day tramps, flounder- 

 ing through bogs, or ascending tall trees. 



As to size, the 4x5 is the best for active field-work, 



