Improvements in Photographic View Finders,
Year: 1898

page_text: Date of Application, 6th Aug., 1898
PROVISIONAL SPECIFICATION.
Improvements in Photographic View Finders,
We, CONRAD BECк and HORACE COURTHOPE BECK, both of 68, Cornhill, in the
City of London, Opticians, do hereby declare the nature of this invention to be
as follows:-
This invention relates to improvements in photographic view finders of the so
called "brilliant" type in which no ground glass or other screen is employed.
In this class of instrument it is well known that unless the eye is in line with
the centre of the lens system the view appearing to the eye does not correspond
with the actual view included in the camera, and that if the eye is moved from
side to side the view included in the view finder will change consequently the
finder ceases to be of practical use.
According to our invention we construct a view finder of the "
brilliant" type
in which the view included is always the same at whatever position the observer's
eye is placed.
In carrying our invention into effect we construct a view finder in which the
image formed in the same plane as the mask or aperture which limits the pic-
ture or view, and we employ an optical apparatus consisting of a lens or lenses
which enables the whole of the image to be seen at one time.
We preferably construct our view finder in the following manner.
At a
In front of a mask or diaphragm, having an aperture of the same shape as the
photographic plate or film, we place a lens or a combination of lenses of such a
focus and at such a distance as to produce an aërial image situated exactly on the
plane of the mask corresponding to the image of the lens of the camera.
suitable distance in the rear of the mask we place an optical apparatus above re-
ferred to which enables the observer to view the whole of the image at the same
time. When it is desired to view the image at right angles to the axis of the
lens of the camera we employ a mirror at an angle of 45° as is well understood.
This mirror may be used to reflect the image from the lens nearest the object
towards the mask or it may be employed to reflect the image from the mask to-
wards the optical apparatus above referred to or the mirror may be placed so as to
reflect the image from the optical apparatus to the eye of the observer.
The mirror may be placed at any other angle when so desired.
Dated this fith dor of two 1800
Improvements in Photographic View Finders.
We, CONRAD BECK and HORACE COURTHOPE BECK, both of 68, Cornhill, in the
City of London, Opticians, do hereby declare the nature of this invention, and in
[Price Sd.]

page_text: what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to improvements in photographic view finders of the so
called brilliant" type, in which no ground glass or other screen is employed.
In this class of instrument it is well known that unless the eye is in line with
the centre of the lens system, the view appearing to the eye does not correspond
with the actual view included in the camera, and that if the eye is moved from
side to side the view included in the view finder will change; consequently the
finder ceases to be of practical use.
According to our invention we construct a view finder of the "brilliant" type
in which the view included is always the same at whatever position the observer's
eye is placed.
In carrying our invention into effect we construct a view finder in which, by
means of a positive object lens or doublet Tens of the required focus, an aerial
image is formed within the finder in the same plane as the mosk or aperture which
limits the picture or view, and we employ an optical apparatus consisting of
another positive or eye lens which enables the whole of the image to be seen at one
time.
We preferably construct our view finder in the following manner. We fix within
the body of the view finder a mask or diaphragm having an aperture of the same
shape as the photographic plate or film; in front of this mask or diaphragm we
place a positive object lens or a doublet lens, of such a focus and at such a dis-
tance as to produce an aerial image situated exactly on the plane of the mask
corresponding to the image of the lens of the camera. At a suitable distance in
the rear of the mask we place an optical apparatus consisting of a positive or
eye lens above referred to, which enables the qbserver to view the whole of the
image at the same time. When it is desired to view the image at right angles
to the axis of the lens of the camera, we employ a mirror at an angle of 45°, as
is well understood. This mirror may be used to reflect the image from the lens
nearest the object viewed towards the mask or it may be employed to reflect the
image from the mask towards the eye lens above referred to; or the mirror may
be placed so as to reflect the image from the optical apparatus or lens at the back
of the mask to the eye of the observer. The mirror may be placed at any other
angle when so desired.
Our invention is represented in the accompanying drawings, in which:-
Figs. 1 to 4 are axial sections of different forms of view finder constructed
according to our invention.
Fig. 5 is a front view of a movable mask or diaphragm, and Fig. 6 is a per-
spective view of one form of our improved view finder fitted with such movable
mask or diaphragm and with means to partially rotate the same.
In all the views like parts are indicated by similar letters of reference.
A is the body of the view finder, B is the mask or diaphragm having an aper-
ture C of the same shape as the photographic plate or film, D is a positive object
lens or doublet lens of such a focus as to produce an aerial image situated exactly
on the plane of the mask corresponding to the image of the camera, E is an optical
apparatus consisting of a positive or eve lens which enables the observer to view
the whole of the image at the same time, F is a reflector which is fixed at the
required angle, those in the drawings being represented at 45°, to reflect the image
to the eye of the observer G is an aperture through which the image is viewed.
In the view finder shown at Fig. 1, for viewing the image at right angles to
the axis of the lens of the camera, the optical apparatus or eye lens E is placed
behind and parallel with the mask Band directs the rays on to the reflector F which
is placed behind the lens E and reflects the image, through the aperture G placed
above it, to the eye of the observer.
In the view finder shown at Fig. 2, the arrangement of object lens D, mask B
and eye lens E is the same as in Fig. 1; the reflector F is however dispensed with

page_text: and the viewing aperture G is placed immediately behind the eye lens E. With
this view finder the image is viewed in a plane parallel with the axis of the
camera lens.
In the view finders shown at Figs. 3 and 6 the object lens D (see Fig. 3) is
represented as a positive doublet lens, the mask B is placed at a suitable distance
behind the object lens, the mirror F is placed immediately behind the mask, and
the eye lens E is placed above the mirror in the position of the viewing aper-
ture G of Fig. 1. This the aerial image formed by the object lens D in the plane
of the mask B is, by the mirror F, reflected to the eye lens E.
In the view finder shown at Fig. 4 the mirror is placed directly behind
the object glass D) and acts to reflect the image from the latter towards the mask B
which is placed immediately above said mirror, the eye lens E being placed at
the required distance above the mask B and quite close to the viewing aperture G.
With the view finders shown at Figs. 3, 4 and 6, the image viewed, like that
shown at Fig. 1, at right angles to the axis of the lens of the camera.
Referring to the view finder shown at Figs. 5 and 6, the mask 13 is shown
fitted with a movable circular diaphragm K mounted with capability of rotating
in the mask B and provided with a stud I engaging within a slot in a lever H
to which the operating stud or button J is attached. The movable circular
diaphragm K has an aperture C therein of oblong form, which by means of the
lever H can be placed with its long side either vertical or horizontal as may be
required.
By the above described arrangements we are enabled to produce a view finder
of the "brilliant" type giving a fixed image and having no other lenses than the
object and eye lenses and having the mask or diaphragm fixed between the twɔ
lenses at a suitable distance from each.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is;-
1. In a photographic view finder of the so-called "brilliant" type, in which no
ground glass screen is used, the combination of a positive object lens or doublet
lens forming an aerial image within the body of the view-finder, a mask for limit-
ing the picture fixed in the plane in which such image is formed, and another
positive or eye lens parallel with the object lens and fixed at the required distance
to the rear of the mask, substantially as herein described and illustrated in the
accompanying drawings.
2. In a photographic view finder of the so-called "brilliant" type in which no
ground glass screen is used, the combination of a positive object lens or doublet
lens forming an aerial image within the body of the view finder, a mask for limit-
ing the picture fixed in the plane in which such image is formed, another positive
or eye lens parallel with the object lens and fixed at the required distance to the
rear of the mask, a mirror fixed at the required angle behind the eye lens, and a
viewing aperture above said mirror, substantially as herein described and illus-
trated in the accompanying drawings.
3. In a photographic view finder of the so-called "brilliant" type in which no
ground glass screen is used, the combination of a positive object lens or doublet
lens forming an aerial image within the body of the view finder, a mask for limit.
ing the picture fixed in the plane in which such image is formed, a mirror fixed
at the required angle behind such mask, and a positive eye lens placed above such
mirror, substantially as herein described and illustrated in the accompanying
drawings.
4. In a photographic view finder of the so-called "brilliant" type in which no
ground glass screen is used, the combination of a positive object lens or doublet
lens forming an aerial image within the body of the view finder, a mirror fixed at
the required angle behind such object lens, a mask fixed above such mirror in the

page_text: plane in which the image is formed by reflection from the mirror, and a positive
eye lens fixed at a suitable distance above the mask, substantially as herein
described and illustrated in the accompanying drawings.
Dated this 24th day of April 1899.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.