How to make pictures : easy lessons for the amateur photographer (1882)
Price, Henry Clay · New York : Scovill Manufacturing Co. · leaf 37
er portion of the drop falling shuts olf the light. If the exposure is required to be still more rapid, a rubber band placed around the tube and stretched up and over the knob E on top of the drop, will accelerate its action. If you wish to copy a painting, engraving, or let- tering, this lens will… … FIG. 9. volving diaphragms, the open- ings of which are adapted to the focal length of their respective lenses. Where only a limited field is required, the full aperture may be used, while with the smaller stops, perfect definition is obtained to the margin of the plate. In selecting lenses of this…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
