14 STEREOSCOPIC PHOTOGRAPHY 



hand. Now close one eye and try to hit the six- 

 pence from the table. You will find that most 

 people will strike the air in front of the table, and 

 miss the coin several times, until they learn to 

 judge by experience of its actual distance from 

 them. 



HINTS ON STEREOSCOPIC PHOTOGRAPHY 



Stereoscopic pictures are taken with two lenses 

 which are separated from one another the same 

 distance as the human eyes. Roughly, this dis- 

 tance is 2| inches. 



The lenses must, of course, be of the same focal 

 length; and, therefore, if any of our readers desire 

 to make a stereoscopic camera for themselves 

 they must see that the lenses are " paired " first 

 of all. My first stereoscopic camera was made 

 in the following way. I bought a second-hand 

 square-bellows half-plate camera, which cost los. to 

 I2S. I then bought from one of the photographic 

 dealers two single achromatic lenses, which cost 

 IS. 6d. each. The dealer kindly allowed me to try 

 the lenses roughly at the time, and I had no 

 difficulty in getting a pair of 6 inches focus. I 

 mounted these, with their centres separated 2f 

 inches, in a lens board on the camera front ; made 

 a " septum " or separator of brown paper, to be 

 fixed inside the camera to divide it into two com- 



