LENSES E0K TUE PHOTOGRAPHIC CAMERA. 183
the objection that they produce some distortion, which is only
to be avoided by greatly reducing the size of the aperture
through which the light falls on the lens, and this necessarily
involves increased sensibility in the preparations we employ.
The distortion is not to tire extent which has been represented,
but it may, by careful examination, be discovered in the finest
photographie portraits to a greater or less extent.