BIRDS OF OUR BUSH 



kindnesses of the elements have an annoying habit of in- 

 truding just at that moment, often waited for during weary 

 hours, when the subject lias plucked up courage to perch in 

 the desired position. By the time these difficulties have 

 disappeared, the bird has disappeared also. 



It will be apparent that the brightness or otherwise of 

 the light would be a matter of little moment if the exposure 

 could be increased as the brightness of the light diminished. 

 Practically all exposures, however, will need to be in- 

 stantaneous on account of the movement of the subject. 

 Time exposures, even short ones, we have found almost 

 always to result in an absolute waste of plates. Pictures 

 of a kind may be, and certainly are obtained in this way, by 

 some photographers, but some slight movement is almost 

 certain to occur which robs the result, to a greater or less 

 degree, of the charm which attaches to sharpness. Birds 

 sitting on their nests are sometimes so still as to afford an 

 opportunity for time exposures, and this is the only cir- 

 cumstance which has led us to experiment in this direction. 

 The picture of the Rufous Fantail reproduced on page 201, 

 and that of the Scarlet-breasted Robin on page 41, are the 

 only bird pictures in this book which are the result of time 

 exposures. 



The length of the exposure is governed by two factors. 

 The first is the size of the aperture used. To the bird 

 photographer this is a simple matter, as it is almost in- 

 variably necessary to use the largest opening provided. In 

 mid-summer, however, the strength of the light may allow 

 of "stopping down" slightly without increasing the ex- 

 posure. If this can be done, it is of great advantage on 

 account of the greater depth of sharpness attained. The 

 second factor is the speed of the plate to be used. In this 

 respect, also, very little latitude is allowed the bird photo- 

 grapher. The plates must be fairly fast, and besides 

 need much more careful treatment in the dark room than 

 do slow ones. The plates we use are marked with a speed 

 number, about 300 H. and D. Uncorrected photographic 

 plates give unsatisfactory results so far as colours (notably 

 red and yellow) are concerned, but "Non-filter" or "Anti- 

 screen" plates of different makes we have found to give 

 much better results in this respect. 



But the greatest tax on the patience of the photo- 

 grapher is the general disinclination of birds to be dealt 



46 



