ZENTMAYER WIDE-ANGLE LENS
Joseph Zentmayer, Philadelphia, Pennsylvania Mid-1860's
- Early 1880's
This globe-style lens design was patented by Joseph
Zentmayer on May 29, 1866, under Patent No. 55,195 for a "Combination of
Lenses for Photographic Purposes". In
Zentmayer's own words taken from the patent:
"The
nature of my invention consists in arranging a doublet of meniscus lenses of
different curvatures but with their exterior surfaces concentric, the lens with
the longest radius being used as the front lens of the combination; then in
using the front lens of such a combination as the back lens in combination with
one of still longer focus or radius to form an instrument of larger size or longer
focus."
Coming to America from Germany, Zentmayer established his
own shop in Philadelphia in 1853, building microscopes and other optical apparatus.
Zentmayer manufactured this doublet style wide-angle lens, beginning in the latter
1860's, with advertisements found for his lenses through at least 1882. This example features a rotating aperture (or
wheel stop), with the 1866 patent date engraved on it alongside Zentmayer's
name. A simple (but effective) shutter
was incorporated, consisting of a sliding bar with a single blade at the end. When pushed inward, the blade blocked the
light from entering, thus eliminating the need for a lens cap.
By the mid-1870's wide-angle designs by Richard Morrison
and other lens makers had taken hold, and the popularity of Zentmayer's lenses
began to decline. Despite having been
manufactured for a number of years, production was relatively low given the few
lenses that survive.
Joseph Zentmayer was well known for his microscopes and
telescopes, and the build quality of this lens is exceptional. His products were highly regarded during his
lifetime, and continue to be, among collectors today.
U.S. Patent and
Trademark Office
Shutter
rod set in the open position