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Telephotography: An Elementary Treatise On The Construction And Application Of The Telephotographic Lens | by Thomas Rudolphus Dallmeyer



This treatise is addressed to those who practise photography either for pictorial or scientific ends.

TitleTelephotography: An Elementary Treatise On The Construction And Application Of The Telephotographic Lens
AuthorThomas Rudolphus Dallmeyer
PublisherWilliam Heinemann
Year1899
Copyright1899, William Heinemann
AmazonTelephotography and Telephotographic Lens

By Thomas R. Dallmeyer, F.R.A.S. Vice-President Of The Royal Photographic Society

With Twenty-Six Plates And Sixty-Six Diagrams

Dedicated To The Memory Of My Father John Henry Dallmeyer B. 1830 - D. 1883 Famed For His Work Himself Beloved

Telephotography
-Preface And Historical Notes
This treatise is addressed to those who practise photography either for pictorial or scientific ends. The late Michael Faraday once remarked : Lectures which really teach will never be popular; lect...
-Chapter I. Properties Of Light
Light consists of vibrations of a highly elastic solid medium termed ether, which pervades all space. These vibrations are conveyed to the brain by means of our eyes, and produce the sensation of sigh...
-Chapter II. The Formation Of Images By The "Pinhole Camera," And Its Perspective Drawing
The simplest of all devices for forming an image is what is termed a Pinhole Camera. If we make a minute hole in a thin sheet of card or metal, and place this at one end of a [rectangular] light-ti...
-The Formation Of Images By The "Pinhole Camera," And Its Perspective Drawing. Part 2
In Fig. 4 reference has been made to the lengths of the images a' b'. a b, a b corresponding to a b at different distances of the screen from p, or different camera-extensions as they are termed. T...
-The Formation Of Images By The "Pinhole Camera," Its Perspective Drawing. Part 3
In ordinary photographic practice, the camera is usually brought very near to the chief object of interest, so as to give it prominence by obtaining a sufficiently large image. When this takes place, ...
-Chapter III. The Formation Of Images By Positive Lenses
The laws of reflection and refraction of light at plane and spherical surfaces are contained in every elementary treatise on Optics.* The reader will do wisely to master them, although an intimate k...
-The Formation Of Images By Positive Lenses. Part 2
Let us now proceed to determine the elements of a lens necessary for assigning the position and 7nagnitude of the image of any object. They are termed the four cardinal points of a lens:* the two p...
-The Formation Of Images By Positive Lenses. Part 3
Fig.17. To express these relations numerically we must introduce an optical law, known as the Law of Conjugate Foci which may be deduced from the geometrical construction above. If we plot cf an...
-The Formation Of Images By Positive Lenses. Part 4
It is important for following our subsequent reasoning that the reader should always refer the distance of the object from the lens to a multiple of the focal length of the lens, but bear in mind that...
-The Formation Of Images By Positive Lenses. Part 5
If both lenses shown in Fig. 22 are considered thin, the centre c of the equi-convex lens is equidistant from both focal points ff'. In the positive meniscus, however, of the same focal length as the ...
-The Formation Of Images By Positive Lenses. Part 6
Fig.24. Glass has a higher refractive index than air (roughly 1.5), thus the angle will be less than . On meeting the second surface of the glass at c, b c forms the same angle ...
-Chapter IV. The Formation Of Images By Negative Lenses
If we present either surface of a negative or concave lens to a beam of rays parallel to the axis of the lens, we shall be unable to find a real image of the object from which the parallel rays emanat...
-The Formation Of Images By Negative Lenses. Continued
From Figs. 30 and 31 we see that as the object approaches the lens from infinity the size of the virtual image increases and approaches the lens. If the object be brought up to the plane coinciding wi...
-Chapter V. The Formation Of Enlarged Images
Part I. By two Positive lens-systems. Part II. By a Positive system and a Negative system combined - or the Telephotographic Lens. PART I. Every positive lens, as we have seen, is capable of formin...
-The Formation Of Enlarged Images. Part 2
Parallel rays incident upon the lens a (Fig. 39) used alone converge towards the focus f at a definite distance from the lens a ; similarly, parallel rays incident upon b diverge as from the virtual f...
-The Formation Of Enlarged Images. Part 3
On increasing the separation (3), or making d a definite quantity, the focal length decreases until d=f2, or the whole separation a =f1 when the image is formed in the centre of the negative lens, and...
-The Formation Of Enlarged Images. Part 4
Plate X [E. &.H.Spitta,Photos. Upper Picture, View of the Saas Grat from Saas Fee. Photographed with Ross 3-inch portable symmetrical F/64 yellow screen. Edward's iso-medium plate, exposure three s...
-Method B. Telephotographic Lens Consisting Of Two Separate Parts
Let us now consider the Telephotographic lens as consisting of two separate parts. The positive element may be considered as forming an image of definite size, of a given object, dependent upon its f...
-Method B. Telephotographic Lens Consisting Of Two Separate Parts. Part 2
By treating the lens in this manner we do not necessarily know the separation of the principal points or planes of the two components, and for distant objects the knowledge of the distance between the...
-Method B. Telephotographic Lens Consisting Of Two Separate Parts. Part 3
Knowing that F=15 5/9, the distance between object and image to bring about the magnification of 1/2 must be (or would be thought to be) 4 1/2 f or 70 inches ; but (neglecting the separation of posi...
-Chapter VI. The Use And Effects Of The Diaphragm, And The Improved Perspective Rendering By The Telephotographic Lens
In determining the position and magnitude of the image of an object we have hitherto only made use of certain functions of a lens or lens-system, and, moreover, considered the latter as perfectly free...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 2
Scale, 3/4. Fig. 48* exhibits at a glance the meaning of a rapid as distinguished from a slow lens. For convenience we have illustrated a lens of 4 inches focal length, but it is evident that t...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 3
It will be found, however, that when the lens is used to its utmost limits in respect of covering power, whatever stop is employed, the angle included is approximately a constant for any extension of ...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 4
Plate XVI Telephotograph of an Encampment taken from a balloon at a height of 800 metres by Captain Mario Moris. Plate XVII rendering of a square or rectangular object as shown in the figure. ...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 5
In the case of employing a very small stop in the lens, all objects may, as a matter of fact, appear equally defined in the image, but as soon as we use a considerable aperture we see at once how obje...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 6
In general, if we take i as the limit of indistinctness permissible in the image, and we reproduce the object in the proportion of n : i, the circle of indistinctness for any point in the field of the...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 7
= 100af + f........(22) or 100 times the effective aperture multiplied by the focal length 4- the focal length of the lens ; or = 100 If2 +f .......(22a) When we focus upon a near object the front d...
-Diaphragm, Improved Perspective Rendering By Telephotographic Lens. Part 8
We may now proceed to consider the magnification to be given by the negative element with which it is combined to form the Telephotographic system. Let the negative element have a focal length of 6 in...
-Chapter VII. Practical Applications Of The Telephotographic Lens
I. - In Portraiture It is probably a matter of common observation that the finest portraits are produced by photographers having the advantage of a long studio. Where the studio is sufficiently long...
-Practical Applications Of The Telephotographic Lens. Part 2
Plate XXI Facade, San Michele, Lucca. Taken with an ordinary lens 12-in. focal length. {Copyright of and kindly lent by J. W. Cruicltshank, Esq.) Plate XXII South-West Corner, Second and Third ...
-Practical Applications Of The Telephotographic Lens. Part 3
Fig. 57. Dr. Miethe, of Messrs. Voigtlander, Brunswick, adopts the method of employing a portrait combination of high intensity as positive element, added to a triple cemented negative, in his cons...
-III. - Groups And Hand-Camera Work By Means Of The Telephotographic Lens
It will have been observed from the premisses that if we include a foreground subject, such as a figure, under a large angle, we must, in order to obtain a sufficiently large image from a given standp...
-IV. Telephotography For Distant Subjects
The application of the Telephotographic lens for photographing distant objects has been that most generally employed. In this connection the Telephotographic lens does not differ in its performance fr...
-IV. Telephotography For Distant Subjects. Continued
It will be observed that the same negative lens is used in both cases ; if combined with the single cemented positive lens the curved surface faces the ground glass, but when used in conjunction with ...
-Chapter VIII. Working Data
The camera and stand must be perfectly rigid. A large tripod head and a bigger clamping screw than usual are advantageous. When long extensions of camera are employed, either a strut attached to the t...
-Abridged Formula For Reference. Positive Lens
If f represents the focal length of an ordinary positive lens, nf any multiple of it, By the law of conjugate foci: f2 =xy..........(1) where x=nf, and y=1/nf. If o be the distance of any object fro...
-Reference
Concave Achromatic Glass Lens, etc. Proceedings of tlie Royal Society. Peter Barlow, F.R.S., and G. Dollond, F.R.S., February and May 1834. Eclipse du 28 Juillet 1851, Relevee Heliographiquement,...









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