2^8 
Camera Craft. 
r The Emu 
|_ April 
With a six-inch lens two feet from an object six inches in 
length, an image of two inches in length will show on the screen, 
and at five feet about half an inch. For every inch the subject 
is longer or shorter than six inches, add on or take oft one-sixth 
of the length of the image mentioned. Thus, the image for a 
six-inch bird at two feet is two inches, a seven-inch bird will be 
two and a third inches, one live inches in length will measure 
about one and two-thirds of an inch on the screen, while the 
eight-inch bird will show an image of two and two-thirds of an 
inch, and four inches will appear on the glass as one and one- 
third inches. 
Natural obstructions will always cause a modification in the 
use of this scheme. For instance, it is sometimes impossible to 
work to this formula in a tree. Even so it has its advantages, 
as a reference to the scale will intimate whether the results justify 
the attempt, as the distance from the nest and the size of the 
picture is approximately known. It is useful to mark the nega¬ 
tive with the scale letter, which serves as a guide if an enlarge¬ 
ment to natural size is required. 
Sharply defined large printing pasted on a piece of cardboard 
six inches by three will help to gain accuracy in focussing, and 
also convey some idea of the relative size of the image if the 
length of the bird is known beforehand. The piece of cardboard 
is placed where you observe that the bird alights or rests during 
its visits to the nest. Focus on this, using the largest aperture, 
until a perfectly sharp image is obtained. If the light will allow 
quick shutter work, and the bird is amenable to the camera, stop 
down to a smaller aperture. By this means greater depth is 
attained, and consequently a better picture of the bird and its 
nest or nestlings. 
On the contrary, if the bird is active and quick in movements 
to and from the nest, a larger aperture and shorter exposure is 
necessary. The times of exposure vary from A to 100th of a 
second on nesting subjects, and the operator will do well to study 
rapidity of movement in birds and the light if best results are 
sought. 
Individual birds vary greatly in temperament within the same 
species. Their habits, on the other hand, are remarkably uni¬ 
form, especially as regards food and nesting habits. Two pairs 
of birds of the same species may be seen nesting in immediate 
proximity to one another. This pair is quiet and fearless, while 
that pair flies away in terror at the least move of the intruder. 
All this behaviour has to be carefully noted before putting up 
the camera, and makes known the extent of hiding to be re¬ 
sorted to, or the distance at which the camera has to be fixed. 
One of the most successful ways of hiding the camera is to 
cover it with a green cloth of medium shade. Sprigs and 
branchlets of the tree, sapling or shrub similar to that in which 
the bird has built, should be fixed over the cloth. The plant 
which contains the nest should not be disturbed any more than 
