18 BIRD STUDIES WITH A CAMERA 
accompanying the contact prints from their respec- 
tive negatives. In each instance the enlargement is 
about three diameters, and the telephoto negative 
of course furnishes the most satisfactory picture. 
9. Lens Test No. 3. Same subject, distance, plate, and date as Tests Nos. 
2and 3. Eight-inch Zeiss Convertible, Series VII a, No. 10, with tele- 
photo attachment; diaphragm F. 8; twenty-one-inch bellows ; one see- 
ond (1/2 second was later found to be full time). 
When the difficulties of telephotography are consid- 
ered, however, and the 3-second exposure of the 
fourteen-inch lens, which permits of hand work, is 
compared with the one second of the telephoto, we 
believe that for general work in photographing 
