Improvements in or connected with Cameras and Optical Lanterns.
Year: 1896

page_text: Date of Application, 20th June, 1896
Complete Specification Left, 22nd Mar., 1897-Accepted. 24th Apr., 1897
PROVISIONAL SPECIFICATION.
Improvements in or connected with Cameras and Optical
Lanterns.
I, ALFRED WRENCH, of 50, Gray's Inn Road, in the County of London,
Manufacturing Optician, do hereby declare the nature of this invention to be as
follows:-
My invention relates to cameras and optical lanterns and has for its object to
provide improved means whereby. the line passing through the axis of the lens
shall always pass through the centre of the plate or slide notwithstanding that the
plane of the lens is placed more or less at an angle to the plane of the object. being
photographed or the screen or to the plane of the sensitive plate or transparency,
thereby obviating the distortion of the image or picture.
By the use of this invention the employment of the ordinary swing-back adjustinent
of cameras is rendered unnecessary.
In carrying out my invention the lens is mounted in such a manner that it can'
be moved through an arc of a circle the centre of which is in the centre of the
sensitive plate or lantern slide.
In practice the mount may be so arranged that the lens can have either a
vertical or a lateral adjustment or both. For a vertical or lateral adjustment the"
motion of the lens is around the surface of a cylinder whilst when both movements
are desired it is on the surface of a sphere.
I can provide for giving the desired movement to the lens by making the camera
or lantern front movable relatively with the body portion thereof or by mounting
the lens on a universal joint.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
: COMPLETE SPECIFICATION.
Improvements in or connected with Cameras and Optical
Lanterns.
I, ALFRED WRENCH, of 50, Gray's Inn Road, in the County of London,.
Manufacturing Optician, do hereby declare the nature of this invention and in what
minnner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention relates to cameras and optical lanterns and has for its object to
provide improved means whereby the line passing through the axis of the lens
shall always pass through the centre of the plate or slide notwithstanding that the
plane of the lens is placed more or less at an angle to the plane of the object being

page_text: photographed or the screen or to the plane of the sensitive plate; or transparency,
thereby obviating the distortion of the image or picture.
By the use of this invention the employment of the ordinary swing-back adjustment
of cameras is rendered unnecessary.
In carrying out my invention the lens is mounted in such a manner that it can
be moved through an arc of a circle the centre of which is in the centre of the
sensitive plate or lantern slide.
In practice the mount may be so arranged that the lens can have either a
vertical or a lateral adjustment or both. For a vertical or lateral adjustment the
motion of the lens is around the surface of a cylinder whilst when both movements
are desired, it is on the surface of a sphere.
I can provide for giving the desired movement to the lens by making the camera
or lantern front movable relatively with the body portion thereof.
To enable my invention to be fully understood, I will describe. the same by
reférence to the accompanying drawings, in, which
Figure 1 is a sectional side elevation of a hand camera provided with my
improvements, the mount for the lens being arranged to move upon a cylindrical
surface:
Figure 2 is a sectional plan, the section being taken on the line 2-2 Figure 1:
Figure.3 is a front elevation of a mount moving on a spherical surface, and
Figure 4 is a vertical section of the same:
Figure 5.is an elevation of a modified form of spherical mount, and
Figure 6 is a central section of the same.
In the arrangement of my invention shewn in Figures 1 and 2, a is the camera
box and b is the front wall of a slide e arranged within the said box and adapted to
be, adjusted slightly for focusing purposes, the. outer face of the said wall being
curved to the arc of a circle which, when the said slide cis at say the central point
of its adjustment, will have its centre at the centre of the sensitive plate which the
camera is designed to receive. dis the: sliding front for carrying the lens.e and.
other, parts, the said sliding front having that. surface which is in contact with the
front,b,curved to the same circle as the said front so that the former can slide upon
the latter. fare guide strips fixed to the front b and serving to hold the movable.
front.d.in position, upon the said: front.b.
With this arrangement it will be understood that the axis of the lens e will
always be upon a line radiating from the centre of the plate, except when the
slide e is moved for focusing purposes in which, case the axis of the lens might
intersect the plate slightly above or below the centre of the same.
In cases where
the focusing adjustment is in the lens itself, so that the position of the sliding front
relatively, with the sensitive plate remains unalterable, it will be obvious that the
axis of the lens will always intersect the sensitive plate at the centre.
In Figures 3 and 4 which illustrate the arrangement of a spherical mount, g is
a ring for carrying the lens the said ring being formed upon or attached to a
plate which is the segment of a sphere. This plate 4 is adapted to slide between
two other plates i, i which are also segments of spheres and form part of a ring j
designed to be secured to the front of a camera the outer of the said plates carry a
pressure ring for bearing upon the plate h."
The arrangement shewn in Figures 5 and 6 does not differ essentially from that
shewn in Figures 3 and 4, the main difference is that. the plate h which carries the.
lens instead of sliding between two plates i, i slides upon a single plate i screws k, k
attached to the plate i passing through slots 1, in the plate hand. being provided
with nuts k, k' for fixing the said plate in any desired position. As shewn the
slots, only permit of a movement of the mount corresponding with that of the
cylindrical arrangement herein before described but it will be,obvious that, the slots
may be formed to permit of movement in any direction. The modification,last,
described is specially adapted for optical lanterns, but it is to be understood, that
the other arrangements described can also be used with optical lanterns.
When use my invention in combination with an optical lantern I find, it

page_text: advisable to use a single lens or other suitable combination of lenses instead of the
usual quarter plate lens in order to obtain sharp definition over the whole of the
illuminated area.
Having now particularly described and ascertained the nature of my said inven
tion and in what manner the same is to be performed, I declare that what [
olaim is
1. In a camera or optical lantern arranging the lens mount to move about a
cylindrical or spherical surface so that the axial line of the lens shall intersect (or
approximately intersect) the centre of the plate or lantern slide notwithstanding
that the mount is adjusted to place the plane of the lens out of parallelism with
the said plate or lantern slide, substantially as described.
2. The improvements in or connected with cameras and optical lanterns herein-
before described and illustrated in the accompanying drawings.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.