The Camera and its Accessories 5 



the plate, while the distance to the other edge is de- 

 creased. This will have a tendency to sharpen the 

 whole plate equally, producing a more uniform nega- 

 tive in less time. 



In purchasing a lens, there are several absolutely 

 essential things to be considered perfect definition, 

 depth of focus, covering capacity, and speed. Begin- 

 ner, beware of making the mistake of attempting to 

 economize by using a small lens! If a 4X5 lens will 

 make a certain picture in one second, with the dia- 

 phragm at F i6 > a 5X7 will do it better and in less 

 time, for it is using the centre of the lens. I use on 

 my F and S Graflex 4X5 a 7X9 lens. 



A long-focus lens is desirable for animal photog- 

 raphy, because the greater the length of focus, the 

 larger will be the image, and the less the distortion. 



For several years I have used a Goerz lens, series 

 III, and for all-around work I have found nothing 

 superior, although in some of the new series there 

 are probably better lenses. My lens has an equiva- 

 lent focus of ten and three-quarter inches; but by 

 using the front lens alone, I have a focus of about 

 seventeen inches. This is of great importance to 

 the field photographer; for with the shorter focus at 

 the distance of sixty feet, an object twenty inches 

 high forms an image half an inch in height; while 



