30 OUR INSECT FRIENDS AND FOES 



should have a good extension of bellows, from 

 fourteen to sixteen inches, sufficient to enable 

 one to use the single combination of the lens 

 when photographing objects moderately near 

 the camera. A good rising-front is also im- 

 portant, as well as a rapid means of reversing 

 the back from an upright to an oblong picture. 

 See that the dark-slides are well made, and that 

 they fit quickly and smoothly into place. A 

 focal-plane shutter, although not generally 

 supplied with the ordinary stand camera outfit, 

 is an extra worth careful consideration, because 

 it permits the maximum amount of light to reach 

 the plate during instantaneous exposures. Next 

 to the focal-plane a good roller-blind shutter 

 fitted behind the lens is the best. The tripod 

 should be rigid at its full extension, and have 

 sliding legs permitting of rapid adjustment to 

 various heights. The quality of the lens is all- 

 important, for without a good lens it is impossible 

 to obtain satisfactory results. If a first-class 

 anastigmat with a working aperture of /5 or/6 

 is too costly, then a good rapid rectilinear lens 

 working at /8 should be selected, and it must 

 cover sharply to the edges of the plate at full 

 aperture. Isochromatic plates should always 

 be used, so that as truthful a monochromatic 

 rendering of the colour values as possible may 

 be obtained. My reasons for giving preference 

 to the comparatively small size of the quarter- 

 plate (3iX4j inches) camera are firstly, its lighter 

 weight and greater portability, advantages which 

 one greatly appreciates towards the end of a 

 long day's tramp across country ; and secondly, 



