Improved Means of Focussing in Photographic Cameras such as "Detective" Cameras.
Year: 1892

page_text: Date of Application, 1st Dec., 1892
Complete Specification Left, 1st Sept., 1893--Accepted, 7th Oct., 1893
PROVISIONAL SPECIFICATION.
Improved Means of Focussing in Photographic Cameras such as
"Detective" Cameras.
We, ARTHUR LEWIS ADAMS of 81 Aldersgate Street in the City of London,
Photographic Apparatus Manufacturer, and BENJAMIN FOULKES-WINKS OF
2 Pretoria Avenue, Walthamstow, London, Photographer, do hereby declare the
nature of this invention to be as follows :-
""
This invention relates to photographic cameras-especially cameras of the
character known as "detective or hand cameras and our present improvements
relate more especially to novel means of focussing in such cameras or in connection
therewith and our improvements are as follows:-
For the sake of example we will describe our invention applied to an ordinary
"racking" hand camera that is a camera in which a number of plates or sensitive
surfaces are stored exposed and transferred out of the way by any of the well
known means for racking such plates backward or forwards etc.
A suitable case is made (light-tight) large enough to contain any suitable
"racking" apparatus or to contain any other suitable means of holding one or
more sensitive surfaces for exposure.
Over this "racking" apparatus or the like we provide sufficient space to receive
and hold a vertical reflector or reflecting surface of any desired and suitable
construction.
This vertical reflector faces towards the lens and is enclosed all round except
where the image or picture comes in from the lens and a peep hole or narrow slot
at the top which is domed or otherwise specially formed so as to keep the interior
space as dark as possible in front of our vertical reflector and also has a further
object to keep the eye or eyes of the operator a sufficient distance from said
reflector so as to clearly and sharply define or depict the picture.
The picture image or object to be photographed may be projected on to our
vertical reflector through and by the ordinary or "acting" lens (by means of suitable
mirrors which interpose to divert the said picture on to the said vertical reflector
just before the picture is taken) or we may avoid interfering with the acting lens
and for this purpose advantageously employ a second lens which serves for focussing
purposes only.
This focussing lens is (or may advantageously be) exactly identical in character
with the acting lens (i.e. the lens proper) and thus project the picture etc. to be
taken directly on to the aforesaid vertical reflector and then by looking through
the aforesaid slot the image etc. reflected on the vertical reflector can be clearly
seen while by mounting both said lenses on one sliding front or frame capable of
adjustment (or other means may be employed to move the two said lens in and out
synchronously) the focussing lens and with it the acting lens are simultaneously
moved in or out until the required definition and focussing is obtained and then
(while still looking at the reflected object etc.) the shutter can be released and the
photograph taken at the same time while still looking on the said object on the
screen,
בד
1
1
1003
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.

page_text: "
COMPLETE SPECIFICATION.
Improved Means of Focussing in Photographic Cameras such as
"Detective" Cameras.
We, ARTHUR LEWIS ADAMS of 81 Aldersgate Street, in the City of London,
Photographic Apparatus Manufacturer, and BENJAMIN FOULKES-WINKS of
2 Pretoria Avenue, Walthamstow, London, Photographer, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention relates to photographic cameras-especially cameras of the
character known as "detective" or hand cameras and our present improvements
relate more especially to novel means of focussing in such cameras or in connection
therewith and our improvements are as follows:-
For the sake of example we will describe our invention applied to an ordinary
hand camera in which a number of plates or sensitive surfaces are stored brought
into position for exposure, exposed and thereafter transferred out of the way or
changed by any suitable means.
A suitable light tight case is made large enough to contain any suitable
racking" apparatus or to contain any other suitable means of holding one or
more sensitive surfaces for exposure and thereafter changing same.
Over this "racking" apparatus or exposing chamber or the like we provide
sufficient space to receive and hold a vertical reflector or reflecting surface of any
desired and suitable construction.
This vertical reflector faces towards the focussing lens (hereinafter described)
and is enclosed all round except where the image or picture comes in from said
lens and a peep hole or narrow slot in the hood or cover over same which hood or
cover is domed or otherwise specially formed so as to keep the interior space as
dark as possible in front of our vertical reflector and also has a further object to
keep the eye or eyes of the operator a sufficient distance from said reflector so as
to clearly and sharply define or depict the picture.
The picture image or object to be photographed may be projected on to the said
vertical reflector through and by the ordinary or "acting" lens (by means of
suitable mirrors which interpose to divert the said picture on to the said vertical
reflector just before the picture is taken) or we may avoid interfering with the
acting lens and for this purpose advantageously employ a second lens which serves
for focussing purposes only.
This focussing lens may advantageously be exactly identical in character with
the acting lens (i.e. the lens proper) and is so arranged and mounted as to project
the picture etc. to he taken directly on to the aforesaid vertical reflector and then
by looking through the aforesaid slot the image etc. reflected on the vertical reflector
can be clearly seen exactly as same will be projected through the acting lens on to
the sensitive surface because by mounting both said lenses on one sliding front or
frame capable of adjustment (or other means may be employed to mount and move
the two said lens in and out synchronously) the focussing lens and with it the
acting lens are simultaneously moved in or out until the required definition and
focussing is obtained and then (while still looking at the reflected object etc.) the
shutter can be released and the photograph taken at the same time while still
looking on the said object on the screen or reflector.
And in order to more fully explain this invention and the manner of carrying
same into effect we will proceed to further describe same with reference to the
drawings hereunto annexed.

page_text: Fig. 2 is a perspective view of the said camera showing the focussing hood or
cover thrown up ready for use and the front also of the camera open ready for
giving exposure.
Fig. 3 is a side view of the camera with part of the side thereof broken out to
show the arrangement of the focussing chamber and vertical reflector therein.
Fig. 4 is a local sectional view on line 1-1 Fig. 3 looking in the direction of the
arrow x.
Fig. 5 is an end view in elevation of the back end of the camera.
a is the camera case.
b is a flap door or cover hinged to the top of the camera case and carrying on its
underside the opaque material e which may be made capable of doubling up and
folding flat when the lid b Fig. 2 is shut down as in Fig. 1 or this hood or screen
may be made of a rigid material of a suitable form so that when the door bis
raised this hood will form an approximately light tight chamber equivalent to the
aforesaid folding hood c.
d is a narrow slot or peep-hole in said hood.
e is a vertical reflector of any suitable form and material which is mounted in a
vertical position in the focussing chamber and immediately opposite the focussing
lens g.
h is a movable front or sliding frame capable of adjustment as hereinafter
explained.
i is the acting lens or lens aperture through which the photograph is taken.
jis a turn button by rotating which a pinion (not shown) on the axis thereof gears
with a rack (not shown) fixed to the said movable front thereby said movable
front is moved towards or away from the vertical reflectore and sensitive surface k
whereon the exposure is to be made.
Thus the focussing lens g is in the same relative position to the focussing surface e
as the actual lens i is to the sensitive surface k (Fig. 3) and g and i being both
mounted upon the same movable front the adjustment of by means of device j
or any other equivalent or suitable device for adjusting in and out so as to clearly
define the object on the reflector e will thereby exactly focus the object to be
photographed on the sensitive surface at k and while the operator thus focusses and
sees the object on the reflector e by placing the eyes close to the slot or aperture d
and moving in or out the adjustable front the focus is obtained and the shutter
can be operated and the photograph taken while still watching the object depicted
on e.
It will be understood and by reference to Fig. 3 be clearly seen that the focussing
chamber is entirely a separate and distinct chamber from the chamber containing
the sensitive surfaces-such chamber for containing and exposing the said sensitive
surfaces (films plates etc.) being of course light tight and of any suitable form and
construction.
Also the said sensitive surfaces may be arranged stored and mounted in any
suitable manner in such chamber and may be changed or moved into position for
exposure and thereafter removed or stored or changed in any well-known or
suitable or desired manner as the construction of this exposing chamber and the
actuation of the sensitive surfaces (i.e. the bringing of same into position for
exposure and removal thereafter) form no part whatever of our present invention
provided that such chamber and the actuating of the sensitive surfaces are suitable
for use in conjunction with a separate focussing chamber such as f and a vertical
reflector such as e therein and a hood thereover.
A second hood (similar to b c d) may be arranged in the side of the camera so as
to be available for use when the camera is to be used on its side instead of vertically
this second hood consisting of a flap or door m hinged to the side of the camera
with a folding part n corresponding to c and slot o therein corresponding to d—this
hood and slot m no communicating with the focussing chamber (exactly as
described with reference to b c d) so that on looking through the narrow slot or

page_text: aperture o the object depicted through the lens g is clearly seen reflected on the
said vertical reflector e.
By this invention we thus provide means to show a true and exact picture of
the object being photographed i.e. of the same size and in all respects the very
same as the impression that the sensitive surface will receive-with the advantage
of enabling the operator to still watch said picture on the reflector while giving the
exposure to the sensitive surface.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In a photographic camera of the character described having an acting lens
communicating with the exposing chamber in the usual or any suitable way, a
second or focussing lens distinct from said acting lens and means to simultaneously
and correspondingly adjust and bring into focus both said lenses in combination and
acting in conjunction with a focussing chamber communicating with said focussing
lens and separate and distinct from said exposing chamber, a vertical reflector at
the back of said focussing chamber and a raised cover or hood-over the latter and
having an aperture therein over said reflector-to keep the latter sufficiently dark
and at same time to keep the eye of the operator at a sufficient distance to show
clearly the picture or object depicted on the reflector substantially in the manner
and for the purposes hereinbefore described.
2. In a photographic camera of the character described-the arrangement and
combination with a camera case such as a of a focussing chamber such as f, a
vertical reflector e at the back end thereof a focussing lens g communicating with
said chamber and an adjustable front or part such as h carrying said lens g and
also carrying the acting lens i means to adjust said front in and out and a raised
cover or hood such as formed by bc collapsible as shown or fixed rigid and a
narrow siot or aperture such as d therein to keep the eye of the operator at a
sufficient distance from the reflector e as to clearly show the picture or object
depicted thereon substantially as and for the purposes described and as represented
in the drawings hereunto annexed.
Dated this 1et dor of Sontember 1893
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.