The difference that we
have in practice is due to the fact that the velocity is uniformly
accelerated. In order to increase the amount of the effective time, it
will be only necessary to increase the aperture of the shutter and apply
again the method that we have just pointed out.
[Illustration: FIG. 3.]
So much for the material part of the apparatus. It will be necessary
in addition to acquire sufficient individual experience to be able to
estimate the intensity of the light, and consequently to judge of the
diaphragm to be employed and the velocity to be obtained. It must not
be forgotten that such or such an object having a relatively slow speed
will not be sufficiently sharp on the negative if it is too near
the apparatus, while such or such another, much more rapid, might
nevertheless be caught if sufficient distance intervened. Here it is
that will appear the skill of the amateur, who will find it possible to
obtain the said object as large as possible and with a maximum degree of
sharpness.
Pages:
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178