78 Photography for the Sportsman Naturalist 



ance with the extension of bellows used and varies 

 according to the speed of the positive lens. One 

 must learn for himself, which he can do by a little 

 experimenting, just how much longer exposure it 

 is necessary to give when using the telephoto 

 attachment, and in just what proportion to in- 

 crease it as he increases the length of bellows. 



Roughly speaking, about four times the length 

 of exposure is needed when the magnification does 

 not exceed two and a half to three diameters as 

 would be required with the ordinary lens, and this 

 increases proportionately to the number of magni- 

 fications. 



Another great advantage of the telephoto lens 

 over one of the ordinary type is that it shows much 

 better perspective. With its use we get none of 

 that grotesque foreshortening which it is almost 

 impossible to avoid when using the short focus 

 lenses on near-by objects, and which often does 

 much to mar the beauty and usefulness of an 

 otherwise successful picture, if, indeed, it does 

 not ruin it entirely. 



The telephoto may be used successfully in the 

 reflex, but only in bright sunlight and by the ex- 

 ercise of the greatest care, for it would be impos- 

 sible to hold the camera absolutely immovable 

 during an exposure exceeding a fifth of a second. 

 It can be used, however, with entire success on 

 birds and animals in cases where they would not 



