34 Photography for the Sportsman Naturalist 



facts that the use of two lenses made it unneces- 

 sarily expensive, while the increased size made it 

 cumbersome and heavy. So the manufacturers 

 set themselves to remedy these defects, and the 

 result was the reflex camera, an instrument that 

 no nature worker can afford to be without. Its 

 principles are the same as were those of the twin 

 lens, which it has practically superseded, with the 

 exception that there is only one lens used by 

 which both the focussing is done and the expos- 

 ure made. This is accomplished by means of a 

 mirror, placed between the lens and the plate, so 

 arranged that, by pressing a button, a spring is 

 released that throws it up and out of the way a 

 fraction of a second previous to the release of the 

 shutter. As it is obvious that the shutter must 

 be back, and not in front, of this mirror, naturally 

 the focal plane is the only one that can be used 

 on this camera. 



It can easily be seen that this instrument has 

 all of the advantages of the twin lens, together 

 with some added virtues. With it pictures can 

 be obtained with comparative ease that were, 

 heretofore, thought to be entirely out of the 

 question ; and so much do I depend upon it in 

 my work, that I should almost feel inclined to 

 advise a man who could only afford one camera 

 to get the reflex. 



When buying a camera, no matter of what type, 



