 |
Claims  |
|
|
I claim:
1. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto print, said camera comprising:
an objective lens;
manually operated means for selecting a pseudo telephoto field of view
reduced from the actual field of view of said objective lens;
exposure control means including a photosensitive element disposed to
receive ambient light; and
light control means, responsive to the selection of a pseudo telephoto
field of view, for controlling the amount of light reaching said
photosensitive element in accordance with the amount of light available to
the pseudo telephoto field of view, whereby the portion of the film frame
covered by the pseudo field of view can be more accurately exposed.
2. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto or pseudo panoramic print, said camera comprising:
an objective lens;
manually operated means for selecting a pseudo telephoto or pseudo
panoramic field of view reduced from the actual field of view of said
objective lens;
means cooperating with said manually operated means for encoding a film
frame with indicia representative of a selected pseudo telephoto or pseudo
panoramic field of view to identify the portion of the film frame covered
by the selected pseudo field of view;
exposure control means including a photosensitive element disposed to
receive ambient light; and
light control means cooperating with said manually operated means for
controlling the amount of light reaching said photosensitive element in
accordance with the amount of light available to the selected pseudo
telephoto or pseudo panoramic field of view, whereby the portion of the
film frame covered by the selected pseudo field of view can be more
accurately exposed.
3. A camera as recited in claim 2, wherein said light control means
includes adjustable means for preventing the amount of light reaching said
photosensitive element from exceeding the amount of light available to the
selected pseudo telephoto or pseudo panoramic field of view.
4. A camera as recited in claim 2, wherein said light control means
including variable masking means for masking said photocell in different
amounts corresponding to the selected pseudo telephoto or pseudo panoramic
field of view.
5. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto print, said camera comprising:
an objective lens;
a viewfinder including means for changing the finder field of view
selectively to at least one telephoto field narrower than the actual field
of view of said objective lens;
means cooperating with said changing means for encoding a film frame with
indicia representative of said narrower telephoto field to identify the
portion of the film frame covered by the narrower telephoto field; and
exposure control means including a photosensitive element disposed to
receive ambient light in the finder field of view to control the amount of
light reaching said photosensitive element in accordance with the amount
of light available to said narrower telephoto field, whereby the portion
of the film frame covered by the narrower telephoto field can be more
accurately exposed.
6. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto or pseudo panoramic print, said camera comprising:
an objective lens;
manually operated means movable to respective positions corresponding to
pseudo telephoto or pseudo panoramic fields of view reduced from the
actual field of view of said objective lens;
code means, responsive to movement of said manually operated means to a
position corresponding to a pseudo telephoto or pseudo panoramic field of
view, for encoding a film frame with indicia representative of the pseudo
telephoto or pseudo panoramic field to identify the portion of the film
frame covered by the pseudo field of view;
exposure control means including a photosensitive element disposed to
receive ambient light; and
light control means, responsive to movement of said manually operated means
to a position corresponding to a pseudo telephoto or pseudo panoramic
field of view, for controlling the amount of light reaching said
photosensitive element in accordance with the amount of light available to
the pseudo telephoto or pseudo panoramic field, whereby the portion of the
film frame covered by the pseudo field of view can be more accurately
exposed.
7. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto or pseudo panoramic print, said camera comprising:
an objective lens;
manually operated means movable to a position corresponding to the actual
field of view of said objective lens and to respective positions
corresponding to pseudo telephoto or pseudo panoramic fields of view
reduced from said actual field of view;
code means, responsive to movement of said manually operated means to a
position corresponding to a pseudo telephoto or pseudo panoramic field of
view, for encoding a film frame with indicia representative of the pseudo
telephoto or pseudo panoramic field to identify the portion of the film
frame covered by the pseudo field of view;
exposure control means including a photosensitive element disposed to
receive ambient light; and
light control means for controlling the amount of ambient light reaching
said photosensitive element in accordance with the position of said
manually operated means, whereby the portion of a film frame covered by a
pseudo telephoto or pseudo panoramic field of view can be more accurately
exposed.
8. A camera as recited in claim 7, wherein said light control means is
responsive to movement of said manually operated means to a position
corresponding to a pseudo telephoto or pseudo panoramic field of view for
preventing the amount of light reaching said photosensitive element from
exceeding the amount of light available to the pseudo field of view.
9. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto or pseudo panoramic print, said camera comprising:
an objective lens adjustable to change its angular field of view within a
field range having a wide angle limit and a telephoto limit;
manually operated means, supported for movement to a plurality of positions
corresponding to respective fields of view within the field range of said
objective lens, for adjusting the lens to a selected field of view, and
supported for movement to other positions corresponding to respective
pseudo panoramic or pseudo telephoto fields of view outside the field
range of said objective lens when the lens is adjusted to said wide angle
or telephoto limit;
code means, responsive to movement of said manually operated means to a
position corresponding to a pseudo panoramic or pseudo telephoto field of
view, for encoding a film frame exposed with said objective lens at its
wide angle or telephoto limit with indicia representative of the pseudo
field of view to identify the portion of the film frame covered by the
pseudo field;
exposure control means including a photosensitive element disposed to
receive ambient light; and
light control means cooperating with said manually operated means for
controlling the amount of light reaching said photosensitive element in
accordance with the respective positions of the manually operated means,
whereby the portion of a film frame covered by a pseudo panoramic or
pseudo telephoto field of view can be more accurately exposed.
10. A photographic camera for exposing a film frame for use in producing a
pseudo telephoto print, said camera comprising:
an objective lens adjustable to change its angular field of view within a
field range having a telephoto limit;
a viewfinder having a finder lens adjustable to change the finder field of
view to respective fields within said field range of the objective lens
and to a plurality of telephoto fields narrower than the possible fields
of said objective lens;
means, coupled with said objective lens and said finder lens for adjusting
the finder lens and the objective lens selectively to similar fields to
view a selected similar field through said finder lens, and for adjusting
the finder lens selectively to said narrower telephoto fields to view a
selected telephoto field through said finder lens when said objective lens
is at its telephoto limit;
means, responsive to adjustment of said finder lens to a selected narrrower
telephoto field, for encoding a film frame exposed with said objective
lens at its telephoto limit with indicia representative of the selected
telephoto field to identify the portion of the film frame covered by the
selected telephoto field;
exposure control means including a photosensitive element; and
optical means for directing ambient light in the finder field of view onto
said photosensitive element to control the amount of ambient light
reaching the photosensitive element in accordance with the selected
narrower telephoto field, whereby the portion of the film frame covered by
the selected telephoto field can be more accurately exposed.
11. An exposure control for a pseudo telephoto camera having an objective
lens for focusing an image of a subject on a film frame and a manually
operated device movable to select a pseudo telephoto field of view reduced
from the actual field of view of the objective lens to cover only a
portion of the subject, said exposure control comprising:
photosensitive means disposed to receive light reflected from the subject
for providing a measure of the brightness of the light; and
light control means, responsive to movement of the manually operated device
to select the pseudo telephoto field of view, for controlling the amount
of light reaching said photosensitive means in proportion to the amount of
light available to the pseudo telephoto field of view.
12. An exposure control as recited in claim 11, wherein said light control
means includes a viewfinder having a finder lens adjustable to change the
finder field of view to an actual telephoto field of view which is similar
to the pseudo telephoto field of view, and said photosensitive means is
located to receive light in the finder field of view.
13. An exposure control as recited in claim 11, wherein said light control
means includes a masking device for attenuating the light reaching said
photosensitive means in proportion to the amount of light available to the
pseudo telephoto field of view. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to commonly assigned, copending patent applications. Ser.
No. 717,053, filed Mar. 28, 1985 in the name of Donald M. Harvey and
entitled PSEUDO TELEPHOTO--PSEUDO PANORAMIC CAMERA, and Ser. No. 743,470,
filed June 11, 1985 in the name of Donald M. Harvey and entitled PSEUDO
FORMAT CAMERA WITH ZOOM FINDER.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a camera for enabling pseudo telephoto
and pseudo panoramic prints to be produced from exposed film frames by
coding a film frame to identify a selected pseudo format. More
particularly, the invention relates to exposure control means in the
camera for regulating the exposure of a film frame in accordance with the
selected pseudo format.
2. Description of the Prior Art
A pseudo telephoto print is one that is made from a central portion of an
exposure having the same width-to-length ratio, e.g., 31/2:5, as that of
the exposure. During the printing process the negative is masked at its
upper, lower, left and right marginal zones, leaving the central portion
of the negative unobscured. Alternatively, the film gate in the enlarger
may be correspondingly masked or adjusted. Then, an enlargement is made of
the central portion of the negative to provide a print with the same
width-to-length ratio as that of the central portion. Thus the print will
have a telephoto or close-up format.
A pseudo panoramic print is one that is made from a narrow portion of an
exposure having a greater width-to-length ratio, e.g., 1:3, than that of
the exposure. During the printing process the negative is masked at its
upper and/or lower marginal zones, leaving the narrow portion of the
negative unobscured. Alternatively, the film gate in the enlarger may be
correspondingly masked or adjusted. Then, an enlargement is made of the
narrow portion of the negative to provide a print with the same
width-to-length ratio as that of the narrow portion. Thus the print will
have a panoramic or elongate format.
Commonly assigned U.S. Pat. No. 3,490,844 granted Jan. 20, 1970 discloses a
method of making a print of a selected portion of a subject to be
photographed. The method comprises the following steps: (1) viewing the
subject in the viewfinder of a camera; (2) manually adjusting mechanical
masking members visible in the viewfinder to frame a selected portion of
the subject; (3) exposing the film in the camera to obtain a latent image
of the subject; (4) encoding the exposure on the film with indicia
representative of the selected portion of the subject; (5) processing the
film to obtain a negative of the latent image of the subject; and (6)
sensing the indica to make a print of the selected portion of the subject
from the negative.
When in U.S. Pat. No. 3,490,844 the selected portion of the subject has the
same relative position in the viewfinder as a corresponding portion of the
exposure, enlargement of the portion in the negative will provide a pseudo
telephoto effect similar to the actual telephoto effect provided by a
telephoto lens. Thus a pseudo telephoto print can be made during the
printing process from an exposure taken without a telephoto lens.
Another patent, U.S. Pat. No. 4,357,102 granted Nov. 2, 1982, discloses a
method of making a pseudo panoramic print from an exposure. According to
the method, a window in the viewfinder of a camera has its upper and/or
lower marginal zones masked off by an appropriate insert to provide a
viewing area with a width-to-length ratio greater than 1:2 and preferably
1:3. Exposures are taken with the viewfinder window partially masked and,
during the printing of the negatives, the film gate in the enlarger is
correspondingly masked or provided with an aperture of the same
width-to-length ratio as that of the unobscured portion of the viewfinder
window. Printing paper with a similar width-to-length ratio is used.
Prints can thus be obtained which have a panoramic or elongate format
without using a panoramic lens.
Although U.S. Pat. No. 3,490,844 discloses a method of making a pseudo
telephoto print from an exposure taken without a telephoto lens, and U.S.
Pat. No. 4,357,102 discloses a method of making a pseudo panoramic print
from an exposure taken without a panoramic lens, in each instance the
exposure is made using an objective lens having a single or fixed focal
length, probably around 45 mm. A 45 mm lens is a normal lens, as
distinguished from a telephoto or wide angle lens, and is chosen to enable
normal prints as well as pseudo telephoto or pseudo panoramic prints to be
produced.
DESCRIPTION OF THE CROSS-REFERENCED APPLICATIONS
My first-filed cross-referenced application discloses a camera for exposing
film frames for use in producing pseudo telephoto and pseudo panoramic
prints. The camera makes it possible to obtain a pseudo telephoto print
from a film frame exposed with the objective lens set at a moderate
telephoto focal length, e.g., 80 mm, and to obtain a pseudo panoramic
print from a film frame exposed with the objective lens set at a wide
angle focal length, e.g., 28 mm. This is in addition to obtaining normal
prints from film frames exposed with the objective lens set at a normal
focal length, e.g., 50 mm. By providing a plurality of focal lengths for
the objective lens, a greater range of pseudo telephoto and pseudo
panoramic effects can be obtained as compared to the prior art devices
shown in U.S. Pat. Nos. 3,490,844 and 4,357,102.
In the camera, the objective lens is adjustable to vary its angular field
of view within a field range having a wide angle limit, i.e., 28 mm, and a
moderate telephoto limit, i.e., 80 mm. A manually operated member is
movable to a plurality of positions corresponding to respective fields of
view within the field range of the objective lens, to adjust the lens to a
selected field of view within such field range. Also, the manually
operated member is movable to other positions corresponding to respective
pseudo telephoto or pseudo panoramic fields of view outside the field
range of the objective lens, when the lens is adjusted to its telephoto
limit or to its wide angle limit. Code means, responsive to movement of
the manually operated member to a position corresponding to a pseudo
telephoto or pseudo panoramic field of view, encodes a film frame exposed
with the objective lens at its wide angle or telephoto limit with indicia
representative of the pseudo field of view. This enables the portion of
the negative covered by the pseudo field of view to be identified for
enlargement to produce a pseudo telephoto or pseudo panoramic print.
A liquid crystal display (LCD) masking unit is located in the viewfinder of
the camera to provide various masking configurations in the finder field
to frame a selected portion of a subject to be photographed. The
respective masking configurations of the LCD corresponds to the pseudo
telephoto and pseudo panoramic settings of the manually operated member.
When the LCD is energized in accordance with the respective settings of
the manually operated member, the LCD is rendered opaque to partially mask
the finder field in various degrees. Thus the particular pseudo telephoto
or pseudo panoramic format associated with the selected setting of the
manually operated member may be viewed in the non-masked portion of the
finder field.
Since the camera disclosed in my first-filed cross-referenced application
uses a masking unit to partially mask the finder field in accordance with
the selected pseudo telephoto setting, the view through the viewfinder is
narrowed to the non-masked portion of the finder field. I have improved
this situation in my second-filed cross-referenced application by
providing (in place of the masking unit) a finder lens in the viewfinder
which is adjustable to change its angular field of view to respective
telephoto fields that define the pseudo telephoto formats. As a result, a
selected pseudo telephoto format can be viewed in the full field of the
viewfinder rather than in a (non-masked) portion of the finder field. This
makes it possible for the viewfinder to show a full natural-size image of
the subject to be photographed, which means that the view through the
viewfinder can be on the same scale as the view with the unaided eye.
SUMMARY OF THE INVENTION
According to my invention, a pseudo telephoto-pseudo panoramic camera
includes an exposure control photocell or the like for providing a measure
of the brightness of light reflected from the subject to be photographed.
Light control means in the camera controls the amount of reflected light
reaching the photocell. The reflected light is controlled in accordance
with the amount of light available to a selected pseudo telephoto or
pseudo panoramic field of view reduced from the actual field of view of
the objective lens. This is in contrast to many prior art devices which
control the amount of light falling on the photocell in accordance with
the amount of light available to the actual field of view of the objective
lens. Thus in the pseudo telephoto-pseudo panoramic camera the portion of
the film frame covered by the selected pseudo field of view can be more
accurately exposed.
In a preferred embodiment of the pseudo telephoto-pseudo panoramic camera
according to my invention, a manually operated member is movable to a
position corresponding to the actual field of view of the objective lens
and to respective positions corresponding to pseudo telephoto or pseudo
panoramic fields of view narrower than the actual field of view of the
objective lens. Code means, responsive to movement of the manually
operated member to a position corresponding to a pseudo telephoto or
pseudo panoramic field of view, encodes a film frame with indicia
representative of the selected pseudo field of view to identify the
portion of the film frame covered by the pseudo field of view. A photocell
in the exposure control system of the camera is disposed to receive
ambient light reflected from the subject to be photographed. The amount of
light reaching the photocell is controlled in accordance with the position
of the manually operated member. Thus the portion of the film frame
covered by the selected pseudo telephoto or pseudo panoramic field of view
will be exposed in proportion to the amount of light available to the
selected pseudo field of view.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in connection with the drawings, wherein:
FIG. 1 is a diagram of a pseudo telephoto-pseudo panoramic camera having an
exposure control system in accordance with a preferred embodiment of the
invention;
FIG. 2 is an exploded perspective view of a Porro prism erecting assembly
for viewing an erect image of a subject in the viewfinder of the camera;
FIG. 3 is a partially exploded perspective view of a zoom objective lens, a
zoom finder lens and manually operated means for adjusting the two lenses
in the camera;
FIG. 4 is a partial sectional view of the two lenses and the manually
operated means;
FIGS. 5a and 5b are elevation views of the finder field in the viewfinder,
illustrating use of a liquid crystal display masking unit controlled by
the manually operated means;
FIG. 6 is a diagram of control circuitry in the camera;
FIG. 7 is a chart for explaining how the camera is operated to expose a
film frame for use in producing a pseudo telephoto or pseudo panoramic
print;
FIG. 8 is an exploded perspective view of an exposure control system in
accordance with an alternate embodiment of the invention; and
FIGS. 9a-9e are elevation views of a masking unit for attenuating a
photocell in the exposure control system depicted in FIG. 8, illustrating
various configurations of the masking unit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is disclosed as being embodied in a 35 mm still picture
camera. Because such a camera is well known, this description is directed
in particular to photographic elements forming part of or cooperating
directly with the disclosed embodiment. It is to be understood, however,
that other elements not specifically shown or descibed may take various
forms known to persons of ordinary skill in the art.
Referring now to the drawings, and in particular to FIG. 1, there is shown
a composite of certain details of a still picture camera for use with 35
mm film, such as the various color print films manufactured by Eastman
Kodak Company. The camera includes an objective lens 1 for focusing an
image of a subject being photographed on a frame section F of the film.
Conventional means, such as a pressure plate and a pair of rails, not
shown, support the film frame F in the focal plane of the objective lens
to take the exposure. A direct-view (eye-level) optical viewfinder 3 in
the camera includes a finder lens 5 and a Porro prism assembly 7 for
viewing an erect image of the subject being photographed. Respective
manually operated means 9 and 11 are disposed about the objective lens 1
and the finder lens 5 for adjusting the two lenses before taking the
exposure.
The objective lens 1 in the camera is a known type of zoom lens, that is, a
lens of variable focal length which can be adjusted continuously by
movement of separate groups of elements in the lens to change the focal
length of the lens. This is done in order to vary the angular field of
view (coverage) of the objective lens 1 between a wide-angle limit and a
telephoto limit. Alternatively, a lens assembly may be provided having a
plurality of interchangeable elements for changing the focal length or
angular field of view. As shown in FIG. 1, the objective lens 1 includes a
front element section 13 which moves in a double action path along the
optical axis O-1, first back (rearward) and then forward as the focal
length of the lens is changed from a wide angle limit of, for exmple 35
mm, to a moderate telephoto limit of, for example, 80 mm. Conversely, a
rear element section 15 of the objective lens 1 moves forward along the
optical axis O-1 in an almost smooth, linear path as the focal length of
the lens is adjusted from 35 mm to 80 mm. At the shortest focal length of
the objective lens 1, i.e., the wide-angle limit 35 mm, the front and rear
sections 13 and 15 of the lens are farthest apart and the angular field of
view is approximately 63.degree.. At the longest focal length of the
objective lens 1, i.e., the moderate telephoto limit 80 mm, the angular
field of view is approximately 28.degree.. Thus the field range of the
objective lens 1 is 63.degree. to 28.degree..
The manually operated means 9 for moving the front and rear sections 13 and
15 of the objective lens 1 to adjust the lens to a selected focal length
from 35 mm to 80 mm is shown in FIGS. 1, 3 and 4. FIG. 1 shows the
manually operated means 9 in a rolled-out (flat) elevational form. FIG. 3
shows such means 9 in an exploded perspective form. FIG. 4 shows the means
9 in a sectional form. As seen in FIG. 4, a cylindrical barrel 17 fixed to
the camera body, not shown, supports the front and rear sections 13 and 15
of the objective lens 1 for movement along the optical axis O-1. The fixed
barrel 17 has a semi-annular opening 19 which is bridged in light-trapping
relation by an exterior zoom ring 21 and an interior cam ring 23. The zoom
ring 21 has a knurled outer surface 25 and is secured at an inner surface
27 to the cam ring 23. The respective rings 21 and 23 are supported on
exterior and interior surfaces of the barrel 17 for rotation relative to
the barrel, about the front and rear sections 13 and 15 of the objective
lens 1. The front and rear sections 13 and 15 have respective cam
followers 29 and 31 which project into different-shaped cam slots 33 and
35 in the cam ring 23 to adjust the objective lens 1 from its 35 mm focal
length to its 80 mm focal length. The different shape of the cam slots 33
and 35, and respective settings of the cam ring 23 for adjusting the
objective lens 1 to the 35 mm focal length and the 80 mm focal length, are
depicted in FIG. 1. When, as viewed in FIGS. 1 and 3, the cam ring 23 is
rotated in a clockwise direction C (by turning the zoom ring 21 in the
same direction) from the 35 mm setting to the 80 mm setting of the cam
ring, the front section 13 of the objective lens 1 first moves rearward
and then moves forward because of a curved segment 37 of the cam slot 33.
Simultaneously, the rear section 15 of the objective lens 1 simply moves
forward because of a straight, inclined segment 39 of the cam slot 35.
This movement of the front and rear sections 13 and 15 adjusts the
objective lens 1 to continuously change its focal length from 35 mm to 80
mm.
A pointer 41 is provided on the zoom ring 21 for alignment with respective
indications of the 35 mm and 80 mm settings of the cam ring 23. As shown
in FIG. 3, the indications are embossed on the outside of the cylindrical
barrel 17.
As is apparent from FIG. 1, the cam ring 23 can be rotated in the clockwise
direction C beyond its 80 mm setting (by similarly turning the zoom ring
21) to a plurality of pseudo telephoto settings 120 mm, 160 mm and 200 mm,
without moving the objective lens 1 from its longest (telephoto) focal
length 80 mm. This is possible because of respective, non-inclined,
identical dwell segments 43 in the two cam slots 33 and 35. Conversely,
the cam ring 23 can be rotated in a counter-clockwise direction beyond its
35 mm setting (by similarly turning the zoom ring 21) to a pseudo
panoramic setting, without moving the objective lens 1 from its shortest
(wide-angle) focal length 35 mm. This is possible because of respective,
non-inclined, identical dwell segments 45 in the two cam slots 33 and 35.
Indications of the pseudo telephoto settings 120 mm, 160 mm and 200 mm of
the cam ring 23 and the pseudo panoramic setting of the cam ring are
embossed on the outside of the cylindrical barrel 17, beyond the 80 mm
and 35 mm indications on the barrel, for alignment with the pointer 45 on
the zoom ring 21.
Like the objective lens 1, the finder lens 5 is a known type of zoom lens
which can be adjusted continuously by movement of separate groups of
elements to change its focal length. This is done in order to vary the
angular field of view (coverage) of the finder lens 5 between a wide-angle
limit and a telephoto limit. Alternatively, a lens assembly may be
provided having a plurality of interchangeable elements for changing the
focal length or angular field of view. As shown in FIG. 1, the finder lens
5 includes a front element section 47 which moves in a double action path
along the optical axis O-2, first back (rearward) and then forward as the
focal length of the lens is changed from a wide angle limit of, for
example, 35 mm, to a telephoto limit of, for example, 200 mm. Conversely,
a rear element section 49 of the finder lens 5 moves forward along the
optical axis O-2 in an almost smooth, linear path as the focal length of
the lens is adjusted from 35 mm to 200 mm. At the shortest focal length of
the finder lens 5, i.e., the wide-angle limit 35 mm, the front and rear
sections 47 and 49 of the lens are farthest apart and the angular field of
view is approximately 63.degree.. At the longest focal length of the
finder lens 5, i.e., the telephoto limit 200 mm, the angular field of view
is 12.5.degree.. Thus the field range of the finder lens 5 is 63.degree.
to 12.5.degree. (as compared to the field range of 63.degree. to
28.degree. for the objective lens 1).
The manually operated means 11 for moving the front and rear sections 47
and 49 of the finder lens 5 to adjust the lens to a selected focal length
from 35 mm to 200 mm is shown in FIGS. 1, 3 and 4. As seen in FIG. 4, a
cylindrical barrel 51 fixed to the camera body supports the front and rear
sections 47 and 49 of the finder lens 5 for movement along the optical
axis O-2. The fixed barrel 51 has an internal, annular cut-out 53 in which
is located a cam ring 55. The cam ring 55 is supported in the cut-out 53
for rotation relative to the barrel 51, about the front and rear sections
47 and 49 of the finder lens 5. The front and rear sections 47 and 49 have
respective cam followers 57 and 59 which project into different-shaped cam
slots 61 and 63 in the cam ring 55 to adjust the finder lens 5 from its 35
mm focal length to its 200 mm focal length. The different shape of the cam
slots 61 and 63, and the respective settings of the cam ring 55 for
adjusting the finder lens 5 to the 35 mm and 200 mm focal lengths, as well
as to several intermediate focal lengths 80 mm, 120 mm and 160 mm, are
depicted in FIG. 1. When, as viewed in FIGS. 1 and 3, the cam ring 55 is
rotated in the clockwise direction C from the 35 mm setting to the 200 mm
setting of the cam ring, the front section 47 of the finder lens 5 first
moves rearward and then moves forward because of a curved segment 65 of
the cam slot 61. Simultaneously, the rear section 49 of the finder lens 5
simply moves forward because of a straight, inclined segment 67 of the cam
slot 63. This movement of the front and rear sections 47 and 49 adjusts
the finder lens 5 to continuously change its focal length from 35 mm to
200 mm.
As is apparent from FIG. 1, the cam ring 55 can be rotated in a
counter-clockwise direction (opposite to the direction C) beyond its 35 mm
setting to a pseudo panoramic setting, without moving the finder lens 5
from its shortest (wide-angle) focal length 35 mm. This is possible
because of respective non-inclined, identical dwell segments 69 in the two
cam slots 61 and 63.
A gear 71 couples the manually operated means 9, which adjusts the
objective lens 1 to a selected focal length, and the manually operated
means 11, which adjusts the finder lens 5 to a selected focal length, in a
manner such that rotation of the zoom ring 21 to rotate the cam ring 23
for the objective lens will cause the cam ring 55 for the finder lens to
be similarly rotated. As shown in FIGS. 1, 3 and 4, the gear 71 engages an
arcuate array of teeth 73 on the zoom ring 21 and a like array of teeth 75
on the cam ring 55. When the zoom ring 21 is rotated in the clockwise
direction C to move its pointer 41 from alignment with the "35 mm"
indication on the fixed barrel 17 to alignment with the "80 mm" indication
on the barrel, the objective lens 1 and the finder lens 5 are adjusted
continuously from 35 mm focal lengths to 80 mm focal lengths and the cam
rings 23 and 55 are adjusted to similar settings, shown in FIG. 1. When
the zoom ring 21 is rotated in the clockwise direction C to move its
pointer 41 from alignment wth the "80 mm" indication on the barrel 17 to
successive alignment with the "120 mm", "160 mm" and "200 mm" indications
on the barrel, the finder lens 5 is adjusted continuously from the 80 mm
focal length to a 200 mm focal length and the cam rings 23 and 55 are
adjusted to similar settings. However, the objective lens 5 remains
stationary at its 80 mm focal length. When the zoom ring 21 is rotated in
a counter-clockwise direction to move its pointer 41 from alignment with
the "35 mm" indication on the barrel 17 to alignment with the "PAN"
indication on the barrel, the cam rings 23 and 55 are adjusted to similar
settings. However, the objective lens 1 and the finder lens 5 remain
stationary at their 35 mm focal lengths.
The Porro prism assembly 7 in the viewfinder 3 permits an erect image of
the subject being photographed to be viewed through the finder lens 5 with
the appropriate brightness. A single Porro prism would erect the image,
but would leave it reversed left to right. To correct for this, as shown
in FIGS. 1 and 2, there are provided two Porro prisms 77 and 79 which are
placed hypotenuse to hypotenuse and at right angles to each other. FIG. 2
illustrates a light ray path through the two Porro prisms 77 and 79 to an
eyelens 81. In essence, the two reflecting surfaces 83 and 85 of the prism
77 and the two reflecting surfaces 87 and 89 of the prism 79 cooperate to
turn the image focused by the finder lens 5 upright as well as
right-way-round.
A liquid crystal display (LCD) masking unit 91 is sandwiched between a
conventional Fresnel lens 93 and ground glass viewing screen 95. The
Fresnel lens 93 and the viewing screen 95 in turn are located between the
respective opposite halves of hypotenuse surfaces 97 and 99 of the two
Porro prisms 77 and 79. The LCD masking unit is a variation of a known
type of unit, such as described in U.S. Pat. No. 4,478,493, granted Oct.
23, 1984, and is depicted in FIG. 5B in a masking configuration in the
finder field 101 of the viewfinder 3. The masking configuration
corresponds to the panoramic setting of the cam ring 23 for the objective
lens 1 and the similar setting of the cam ring 55 for the finder lens 5.
As shown in FIG. 5B, the masking unit 91 comprises four sets of
right-angle insulated strips 103 of transparent, electrically conductive
material arranged in side-by-side relation in the respective corner zones
of the finder field 101 and two sets of elongate insulated strips 105 of
the same material arranged in side-by-side relation in the upper and lower
marginal zones of the finder field. Preferably, each set of the
right-angle strips 103 includes three strips, and each set of the elongate
strips 105 includes three strips. FIG. 5A illustrates the finder field 101
as it appears with the masking unit 91 de-energized, which is the
situation when the cam rings 23 and 55 are rotated from their 35 mm
settings to their 200 mm settings or vice-versa. In this instance, the
right-angle strips 103 and the elongate strips 105 are not visible in the
finder field 97. FIG. 5B illustrates the finder field 101 as it appears
with the masking unit 91 energized to provide a pseudo panoramic format,
which is the situation when the cam rings 27 and 55 are in their panoramic
settings. In this instance, the elongate strips 105 in the upper and lower
marginal zones and the right-angle strips 103 in the corner zones are
opaque in the finder field 101. In contrast to the electrically controlled
LCD masking unit 91, a mechanically controlled masking unit may be
provided in the viewfinder 3. An example of a mechanical unit is shown in
U.S. Pat. No. 3,212,422, granted Oct. 9, 1965.
Four light emitting diodes (LED's) 107, 109, 111 and 113 are disposed in
evenly spaced relation in the camera for selective energization to
spot-expose vari | | |
