AN IMPROVED METHOD OF TAKING BINOCULAR OR SPACE PHOTOGRAPHS
Year: 1877

page_text: LETTERS PATENT to Carl Heinrich Lehmann, of Stargard, in Pomerania,
Kingdom of Prussia, for the Invention of "AN IMPROVED METHOD OF
TAKING BINOCULAR OR SPACE PHOTOGRAPHS."
COMPLETE SPECIFICATION filed by the said Carl Heinrich Lehmann at the
Office of the Commissioners of Patents on the 22nd December 1877.
CARL HEINRICH LEHMANN, of Stargard, in Pomerania, Kingdom of Prussia.
"AN IMPROVED METHOD OF TAKING BINOCULAR OR SPACE PHOTOGRAPHS."
It is well known to opticians that a body, if seen with but one human eye,
appears as a plane, and not as a solid or body resting in space. The latter impression
we receive only by catching with the other eye other points and planes of the
object which the one eye cannot behold.
In the art of photographing no method has been hitherto known or used which,
according to theory and experience, produces on the eye in looking at a photograph
an effect or appearance of objects being seen with two eyes, or to use another
expression, as standing free in space, or in relief, and allowing an estimation of the
space between two points more or less distant from the spectator.
It is required or expected in photographic pictures, more than in any other kind
of pictures, that they should produce upon us the impression of reality, or of an
object seen with both eyes. It will be necessary before all that the picture should
not contain any lights, shadows, outlines, and perspectives which would not be seen
with two eyes, and if such be found, nevertheless, they may be called adulterated
lights, shadows, outlines, and perspectives.
By the method hitherto employed in photographing and other uses of the camera
obscura (which method consists in either permitting the rays of light to enter
through the whole-surface of the object glass, or through such part of the same as
does not divide the entering rays) such adulterated lights, shadows, and the like;
must be produced; or if the aperture for the light be very small, and the distance

page_text: .
very large, the object will appear as if seen with one eye only If, however, an
object glass of larger size, quite uncovered, should be used, lights, shadows, outlines,
and perspectives will appear on the picture as they should be seen by one eye with
a pupil as large as the object glass, but such an eye would not see at all.
If, for instance, a photograph were to be made by a sufficiently long, or a suffi-
ciently narrow tube, placed at the lever of the two eyes, and perpendicular upon
the line between the two eyes, so that neither the right nor the left eye could look
through the whole aperture of the tube, the averse aperture should not be visible
upon the picture The picture, taken with the object glass uncovered, will never-
theless show the impression of the light of the full aperture. This light I call
adulterated as well as the perspective.
These adulterated lights and other effects I avoid by my improved method, which
involves the covering of the object glass as herein described. I make the light of
the object fall upon the receiving plate in the same manner as the rays of light
of an object seen enter through the two eyes and unite in the impression of one
picture.
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The lens apparatus, combined with the camera obscura, may be well compared to
the human head. The object glass represents the eye, and the said improved
method chiefly consists in giving the effect of two eyes to this one eye by covering
the object glass in such manner as to make the light enter only through two sepa-
rate apertures. Hence I term the pictures thus produced binocular pictures
Any particular form of the two apertures allowing the light to enter is not
essential, and any suitable material may be used for covering those parts of the
object glass through which the light is not allowed to pass.
In the accompanying Drawing, Figures 1, 2, and 3 shew in what manner the
object glass may best be covered. This method of covering the object glass may be
applied to glasses of any size. With small object glasses care must be taken that
the case projecting to shade the object glass does not too much limit the scope of
view. This difficulty may easily be prevented by suitably widening the case.
The picture will become the more perfect the more nearly it is made in accordance
with the position and construction of the human eyes. For this purpose it is best
to use an object glass of more than 21, inches in diameter. If possible, a space of
2 inches (the average, distance between the pupils of the eyes) should be covered
upon the object glass, and, on both sides of this untransparent space ample space
should be left to admit sufficient light to produce the picture. If I place an object 3
glass thus prepared in opposition to an object in the same place which my eyes had
previously occupied, the rays of light, equal in strength and direction, having before
entered my eyes, will now fall into the eyes of the object glass. The picture thus
produced will in consequence make exactly the same impression with relation
to the proportions of size and distance as if the object were beheld with the
living eyes.
Suppose I should place before the apparatus a globe on which the degrees of
length and breadth had been marked; if the picture shows the degrees from 1 to.
180, or more, the globe must obviously be smaller than 2%, inches in diameter; on
the contrary, it must be larger, or the distance from the object glass must be less
in the same proportion as a smaller number of degrees appear upon the picture.
The size of an object is not estimated by numbering the degrees, but the impres-
sion of it is received by the size of the angle formed by the axis of the eyes in
fixing an object.
With the pictures produced by my improved method the effect will be, the, same. 5
The object of the photograph will always appear more natural and more, agreeable
to the eye than in ordinary pictures
My said improved method may, be applied in any photographic apparatus, no
essential modifications of the usual proceeding being necessary.
Photographic pictures produced by my said Invention may be readily dis- 5
tinguished from ordinary pictures.
Having thus fully described my said Invention, and the manner of performing

page_text: the same, I wish it understood that I claim the improved method of taking or pro-
ducing photographic pictures or photographs by using a photographic apparatus
with its object glass prepared or partially covered by any untransparent fabric or
substance, leaving two separate apertures of convenient form to permit the light to
enter, and whereby I obtain photographic pictures, which I term binocular pictures,
as above described
In witness whereof, I, the said Carl Heinrich Lehmann, have hereunto set
my hand and seal, this Seventeenth day of December, in the year of our
Lord One thousand eight hundred and seventy-seven.
CARL HEINRICH LEHMANN. (L.S.)