Improvements in Photographic Cameras.
Year: 1896

page_text: Date of Application, 24th Nov., 1896-Accepted, 2nd Jan., 1897
COMPLETE SPECIFICATION.
Improvements in Photographic Cameras.
I, PHILIP KOSSUTH STERN, of 613-615, Pine Street, Saint Louis, in the
State of Missouri United States of America Engineer, 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, reference
being had to the accompanying drawings and to the letters and figures marked
thereon, that is to say :-
My invention relates to photographic cameras having an internal mirror for
throwing upward the image while adjusting and focusing the same prior to the
exposure of the plate, and it has for its object to facilitate the adjustment of the
camera and render more clear to the operator the view to which the sensitive film
is about to be exposed, to a greater extent than any other means that I am at
present aware of.
I attain this object by the mechanism illustrated in the arcompanying drawings,
in which:
Fig. 1 is a longitudinal sectional view of my improved camera, and
Fig. 2 a cross section on the line 2, 2, of Fig. 1.
Similar numerals refer to similar parts throughout both views.
The box 1 is divided into the compartments 2, 3, and 4, and is provided with a
lens 5, a holder 6 for the sensitized plate, a focusing screen 8, and a mirror 9,
which constitute the principal part of the camera. To the back of the mirror 9
is secured a rigid back board 10, to the side edges of which are fastened the walls
or flanges 11. Around the board 10 extends a frame or bead 12 which holds the
mirror in position, the board itself serving to protect the mirror against breakage
by concussion or jar.
The mirror and backboard swing about a pivot 13, and are operated from the
outside by a button 14 (see Fig. 2) connected with the frame 12, whereby they
can be raised from the normal position, which is that shown, into the upper part of
the camera to allow the image to fall directly on the sensitized plate. The lens 5
is held in a lens plate 16 whose rear face forms a segment of a circle struck from
the pivot 13. To the free end of the mirror, is secured a corresponding segmental
portion 15, working close against said lens plate 16. This segmental portion 15
(hereinafter termed the mirror shutter) serves to cover the lens aperture 17, prior
to exposing the plate in the holder 6, and to uncover said aperture when it is
desired to make an exposure.
When the mirror 9 is in its normal position, a projection 18 secured thereto
engages a lever 19, pivotted at 20, and raises its end 21, so moving the diaphragm 22
upward sufficiently to bring the largest stop 23 into position in the lens tube 24.
This diaphragm slides in suitable guides 25 and carries the revolving stop 27
provided with various sized apertures 26. This stop projects slightly through the
top of the box so as to permit of easy manipulation.
To the diaphragm 22 is secured an instantaneous shutter 28, which is an ordinary
revolving or pivotted spring shutter of any suitable construction, and is set by a
cord 29 running over a pulley 30 which rotates upon a pivot plate secured to the
upper edge of the diaphragm 22. When the diaphragm 22 has been moved
upward by the lever into the position shown consequent on the return of the mirror

page_text: from its raised position during the previous exposure, the cord 29, being secured at
one end to the staple 31, will be strained so as to energise the shutter spring.
Upon raising the mirror 9 by means of the button 14, the projection 18 will
disengage the lever 19 and allow it and the diaphragm 22, to descend until the
trigger 32 of the shutter strikes a block 33, the effect of which will be to
disengage the end 34 of said trigger from a notch 35 in the shutter, thereby
releasing the latter and making the necessary exposure of the plate or film in the
holder 6. It is obvious that as the diaphragm descends, that aperture in the stop
which has previously been brought into the position 26 (Fig. 1) will register with
the lens.
By this arrangement of the shutter, mirror, and diaphragm, I am enabled to
photograph rapidly moving object, the exposure being effected by simply turning
the button 14, which operates not only the mirror shutter 15, but also the
instantaneous shutter, if desired, thus giving an exposure which will produce a
negative having practically no blurring of the image arising from movement of the
object. This could not be obtained by making the exposure with the mirror shutter
alone, for the reason that the mirror, in its swinging movement, has its velocity
considerably retarded by the enclosed air; and furthermore the exposure would be
accompanied by considerable jar, due to the momentum of the moving piece, which
necessarily would be greater than that of the instantaneous shutter, and would also
tend to produce a blurring of the image.
To give the necessary adjustment of the plate holder 6, as required for proper
focusing, the said holder is connected with the focusing screen so as to work in
unison therewith. For this purpose, a three-armed lever 36 having arms 37, 38, is
mounted on the pivot 13; its arm 37 having a slotted head 39 which engages a
pin 40 attached to the frame 41 of the ground glass focusing screen, while its
arm 38 has a pin 42 engaging a slot in the head 44 of a two armed lever 43. The
other arm 45 of this lever has a slot in which engages a pin 46 secured to the
sliding compartment 4 which carries the plate holder 6. In the drawing,
the lever 36 is moved to its extreme limit in one direction, viz. to the left, but
by moving it to the right, as indicated by the arrow, the arm 37 will raise
the focusing screen 8, at the same time the arm 38 engaging the lever 43 will
move the compartment 4 and the plate holder 6 proportionately further from
the lens 5.
It is obvious that by this arrangement of levers, the photographic image which
is thrown upon the ground glass 8 (the rays being reflected from the mirror 9) may
be focused while, at the same time, the film is brought to the proper distance from
the lens, whereby, when the mirror is raised and the image falls upon the sensitized
surface in the holder 6, it shall be in exact focus.
Obviously, instead of the holder 6 adapted for plates, a holder for films or other
sensitized media might be used.
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 I
claim is :-
1. The improved photographic camera, having its parts constructed, arranged,
and combined to operate, substantially as hereinbefore described with reference to.
the accompanying drawings.
2. A photographic camera, of the kind described, having its diaphragm so
arranged that the largest aperture comes into register with the lens when the
mirror is in its normal position for focusing, while the smaller apertures come into
position when the mirror is raised, substantially as described.
3. In a photographic camera, of the kind referred to, in the preceding claim, the
combination with the diaphragm of an instantaneous shutter arranged to be set and
operated by the movement of the diaphragm, substantially as described.
4. The arrangement of the focusing screen 8 and the holder 6, and the means for
moving the same simultaneously, as and for the purpose described.

page_text: 5. In a photographic camera of the kind described, the combination of a pivotted
mirror having a segmental mirror shutter at its free end, and a diaphragm carrying
an instantaneous shutter and actuated by a lever operated by a projection secured
to the said mirror, substantially as described.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5ª, Market Street, Nottingham,
Agent for the Applicant.