20 PHOTOGRAPHY FOR NATURALISTS. 



Correct exposure mean?, in pure photography, that all 

 subsequent operations may be performed mechanically. 



The matter of apparatus is of such importance to 

 the naturalist, that it merits treatment under separate 

 headings. 



Our first consideration is naturally as to the best 

 form of camera, or cameras. A half-plate stand, and a 

 magazine quarter hand of fixed focus, will be found to 

 fulfil all likely requirements. It is essential that the half- 

 plate should have a long extension, for much of its work 

 will be ll copying" as nearly life-size as possible. It 

 should have square bellows on account of the greater 

 rigidity of a square frame. Appearance is of no conse- 

 quence whatever, and the photographer-naturalist, who 

 wishes to invest in a half-plate camera, could not do 

 better than secure a second-hand one of the old- 

 fashioned heavy brass-mounted models of fifteen years 

 back. Let him avoid the original dark slides and have new 

 ones fitted three will be ample and let him be certain 

 that they are absolutely light-tight, both in themselves 

 and at their junction with the camera. The latter 

 point is of some importance, as in natural history work 

 one has not much time for careful adjustments, or even 

 tor covering the dark slide in the orthodox fashion. In 

 the writer's judgment a dark slide is worthless unless 

 it can stand the full blaze of sunlight when fitted to the 

 camera with shutter drawn. To talk of light " creeping" 

 in", unless the slide is under the protection of the focus- 

 sing cloth, is to confess that either the slide itself or its 

 junction with the camera is defective. If light proceeded 



