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`APPLE V COREPHOTONICS
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`Exhibit 2016
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`APPLE V COREPHOTONICS
`IPR2020-00905
`Exhibit 2016
`Page 1
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`Library of Congress Caraloging-in'Publication Data
`
`Kingslake, Rudolf.
`Optics in photography / Rudolf Kingslake.
`p.
`cm.
`“A Publication of SPIE—the International Society for Optical
`Engineering.“
`Includes bibliographical references and index.
`ISBN 0-8194-0763—1
`1. Photographic optics.
`TRZZOKSG I992
`771.3'5ndc20
`
`Ir Title}
`
`92-1186l
`CIP
`
`Published by SPlE—The International Society for Optical Engineering
`PO. Box 10
`Bellingham, Washington 98217-0010
`Design: Matt Treat
`Composition: Carrie Binschus
`
`Copyright © 1992 The Society of Photo—Optical Instrumentation Engineers
`
`All rights reserved. No part of this publication may be reproduced or distributed
`in any form or by any means without written permission of the publisher.
`
`109876543
`Printed in the United States of America
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`APPLE V COREPHOTONICS
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`APPLE V COREPHOTONICS
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`lb LlldL LllC lllldl LILlllL lllleL UK: VICVVL-U llUlll KPLJIUKllll'ClLCly LLB LUllCLL LCLILCL
`
`ofperspective, so that the angles subtended at the eye by the various images
`in the picture will be the same as the subtense angles of the original objects
`at the camera lens. For contact prints, the center of perspective corre—
`sponds to the actual location ofthe lens in the camera, opposite the middle
`of the picture and distant from it by the focal length of the camera lens. For
`enlargements, the distance of the center of perspective from the print is
`found by multiplying the focal length of the camera lens by the enlarge—
`ment ratio. Thus, for a negative made in a 35mm camera with a 50 mm (2‘
`inch) lens, and enlarged 10 times in printing, the center of perspective is
`at 20 inches from the print, and the picture should be viewed from this
`point. The gain in realism obtained by enlarging small negatives in this way
`is quite marked and often astonishing.
`The lateral position of the eye in relation to the center of perspective
`is also important. This fact explains the serious distortion that results when
`we look at a motion—picture screen from the end of the front row of seats,
`the center of perspective being actually located on a line joining the
`projector to the screen. In planning a large mural, which is to be viewed
`from the floor ofa room, it is advisable to have the camera low and use the
`rising front. The opposite effect, with the camera looking down on the
`subject, would be very unpleasant in such a case.
`
`The Field Covered by a Lens
`
`Every lens projects light onto a circular field that is limited in size by the
`vignetting or cutting of oblique light by the lens barrel. However, in very
`few lenses is the definition sharp to the extreme limit of this circle of
`illumination. Since good definition is required in any practical application
`of the lens, it is customary to state the field of a lens in terms of the angle
`over which good definition is obtainable (Fig. 1.8). This angle generally
`increases somewhat as the lens is stopped down to a smaller aperture.
`Since most photographs are taken on a square or rectangular film area,
`it is necessary that the film format should fit into the circle of good
`definition of the lens. Thus, the diameter of this circle must be equal to, or
`greater than, the diagonal of the film.
`
`The “Normal” Focal Length for a Camera Lens
`For ordinary photography, the ”normal" field is usually such that the
`diagonal of the negative is equal to the focal length of the taking lens. This
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`APPLE V COREPHOTONICS
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`Exhibit 2016
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`APPLE V COREPHOTONICS
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`OPTICS IN PHOTOGRAPHY
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`8
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`
`
`.v‘.\\\i\\\\"'
`,,:.7”,.
`
`(’6‘
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`
`
`CIRCLEOFILLUMINATION
`
`
`CIRCLEOFGCDDDEFINITION
`
`
`,1
`
`Figure I .8. The circle of illumination and the circle of definiIion of 0 lens.
`
`computes to be a total field of 53°, or a half—field of 265°. As has been
`mentioned, this angle is rather wider than the eye can cover at a glance,
`but in practice we tend to View most photographs from a point well beyond
`the center ofperspective, and we unconsciously scan a print with our eyes.
`Such an angle of View is therefore not objectionable. Many photographic
`prints, too. are cropped in printing so that the whole of the lens field is not
`record ed.
`
`A wicle’field lens will cover an angular semifield of about 30° to 35C,
`and a true wide/angle lens will cover a semifield of 45° to 50° (see Fig. 1.9).
`Hence, a given film format will he covered adequately by a wide/angle lens
`having a focal length equal to about half the picture diagonal. Naturally,
`the field covered by the camera will not be increased by using a widerangle
`lens of the same focal length as the normal lens; we can gain field only by
`the use of a shorterathan—norlnal focal length.
`Some narrow—angle lenses are loosely called “telephoto” lenses because
`they have a longer focal length than the normal lens and thus give a
`picture to a larger scale. However,
`the name “telephoto” should be
`restricted to a lens of a particularly compact type of construction (see page
`148), in which the distance from the front of the lens to the film plane is
`
`E.
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`_.
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`45' WIDI: ANULt
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`35° WIDE FIELD
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`24° NORMAL STILL CAMERA
`
`I4° MOTION PICTURE
`
`
`
`(LENS AXIS)
`
`Figure 1.9. Some typical angular fields of lenses.
`
`less than the focal length of the lens.
`In motion—picture photography it has always been customary to use
`relatively long—focus lenses, the “normal" angular semifield being only
`about 14°, This was probably done originally to keep the camera well away
`from the actors in order to give them greater freedom of movement along
`the line ofsight. If the camera were close to the subject, with a short—focus
`lens, the apparent size of the actors would appear to grow or shrink rapidly
`as they moved, and they might even walk completely out of focus in a couple
`of steps! Moreover, the “panning distortion” mentioned on page 20 is less
`noticeable if a long~focus lens is used. The use of a narrow angular field
`greatly helps the lens designer to make wide’aperture lenses of good
`quality, which are very necessary with motion—picture cameras having a
`fixed exposure time.
`The matter ofperspective must not be overlooked in this connection,
`as it is generally desirable that the center ofperspective should fall at about
`the middle of the audience in a theatre. Hence the angular field of the
`camera should be about twice that of the projector, which again brings the
`camera semifield to about 14°. A wide—angle movie lens then covers a half
`angle of about 20°, which is actually less than the field of a normal lens in
`still photography.
`The following table of picture diagonals for some standard film sizes
`may be of interest. They are taken from ANSI Standard PH3.501—1987.
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`APPLE V COREPHOTONICS
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`OPTICS I_\' PHOTOGRAPHY
`10
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`(3) Still cameras
`
`Diagonal
`
`Film name
`Negative area
`(mm)
`(inch)
`Disc and Minox
`8 X 11 mm
`13.6
`0.53
`110
`13X17 mm
`21.4
`0.84
`half 135
`17% X 24 mm
`30.1
`1.19
`126
`28 X 281/2 mm
`40.0
`1.57
`135
`24x36 mm
`44.0
`1.73
`828
`28 X 40mm
`488
`1.92
`
`Sq. 127 (173 X 1%. in.)
`127 (15/9X21/4in.)
`Sq. 120 (ZVpXZI/iiii.)
`120 (21/4 X 31/4in.)
`116
`
`‘A—plate
`
`41 X 41 mm
`41x56 mm
`56X56mm
`56 X 82% mm
`21/2X41/4in.
`
`31/4 X 4% in.
`4 X 5 in.
`5 X 7 in.
`
`58.0
`69.4
`79.2
`99.7
`125.2
`
`135.9
`162.6
`218.5
`
`2.28
`2.73
`3.12
`3.93
`4.93
`
`5.35
`6.40
`8.60
`
`(b) Motionvpic’ture cameras
`
`Normal focal
`Camera
`Projector
`length of
`
`Size
`Frame
`Diagonal
`Gate
`Diagonal
`camera lens
`( mm)
`(mm)
`(mm)
`(mm)
`19.05 X 25.37
`31.75
`17.26 X 23.01
`28.76
`16.03 X 22.05
`27.26
`15.24 X 20.96 25.91
`7.4-2 X 10.22
`12.63
`7.21 X 9.65
`12105
`4.22 X 5.77
`7.15
`4.01 X 5.36
`6.69
`3.51>< 4.80
`5.95
`3.28 X 4.37
`5.46
`
`35mm silent
`35mm sound
`16mm
`Super—8
`8min
`
`2 inch (50 mm)
`2 inch( 50 min)
`1 inch (25 mm)
`1/1
`inch (13 mm)
`1/2 inch (13 mm)
`
`“True” and “Apparent” Perspective
`
`From the preceding discussion it should be clear that if we look at a
`photograph from some point other than its true center of perspective, we
`must expect to see a distorted representation of the original scene. For
`instance,
`if our eyes are considerably too far away from the picture,
`foreground objects will appear too large7 and background objects relatively
`too small. This effect is particularly noticeable in photographs taken with
`a widezangle lens, such as that in Fig. 1.10. The center ofperspective of the
`lower photograph is at about 6 inches from the print, and ifour eye is placed
`there, we have the impression that we are looking at a car from a reasonahle
`distance away. For the upper picture, a wide»ang1e lens was used and the
`camera was moved very close to the car. The center of perspective of the
`
`I
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`p .
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`..
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`APPLE V COREPHOTONICH
`Exhibit 2016
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`APPLE V COREPHOTONICS
`IPR2020-00905
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