410 



Sierra Club Bulletin 



can learn. Details of the outfit and mode of procedure are 

 given herewith in the hope that they will prove of interest and 

 value to others desirous of following up this line of enterprise 

 ^ without undue expense and trouble. 



The belief that good results are to be obtained only by the 

 use of the most expensive type of reflecting camera is not 

 borne out by the facts. On the other hand, one should not ex- 

 pect to secure the best negatives of small living wild animals 

 with the cheapest sort of hand camera. A camera between 

 these two extremes was found in the writer's experience to 

 give excellent results. 



Good pictures were obtained with a "stand" or "tripod" 

 camera which has a focal capacity (bellows) about twice the 

 focal length of the lens used. The camera with which were 

 secured the chipmunk pictures accompanying this paper was 

 adapted to take lo- by 15-centimeter and 3^-by 5^-inch plates. 

 These plates are each of good proportions and of wholly suffi- 

 cient size. A ground glass which registers the exact position 

 that the plates assume in the camera aids accurate focusing. 

 This is of the utmost importance, for when the object photo- 

 graphed is only three or four feet distant from the lens a 

 change in the position of the subject, if only of a few inches, 

 closer to or farther from the camera, throws the image out of 

 focus. 



Metal plate-holders are preferable, as there is less danger of 

 the plates being light-struck when the plate-holders are left in 

 the sun than is the case with wooden holders. A good anastig- 

 mat lens is a wise investment, as with such a lens enlargements 

 three or four times the original size of the negative can be 

 made with little loss of sharpness. A Dagor lens of 6^-inch 

 focal length, a Turner-Reich convertible anastigmat f/6.8 lens 

 of 7^ -inch focal length and a Bausch & Lomb Tessar lens, 

 Series I c, f/4.5, of 7^-inch focal length, have all proven satis- 

 factory for this work. A "speed" lens is not a necessity, since 

 stops 8, II, and 16 are the ones most often used. Larger aper- 

 tures do not give sufficient depth of field when used at a dis- 

 tance of three or four feet, as allowance must be made for 

 slight changes of position by the animal photographed. This 

 difficulty is illustrated in the accompanying picture of the 



