Thomas Rudolphus Dallmeyer | |
|---|---|
 | |
| Born | 16 May 1859 |
| Died | 25 December 1906 (aged 47) |
| Nationality | British |
| Education | Mill Hill School |
| Occupation | optics |
Thomas Rudolphus Dallmeyer (16 May 1859 –25 December 1906), [1] English optician, was the son of John Henry Dallmeyer who ran an optics business. His maternal grandfather, Andrew Ross, was himself the first English photographic optician. [1]
After attending other schools, Thomas enrolled at Mill Hill School where he came under the tutelage of Dr. J.A.H. Murray who is best known as an editor of the Oxford English Dictionary . After leaving school, he entered his father's optometry business, while learning the theoretical side from Oliver Lodge. [1]
When Thomas was twenty-one, his father went on a long voyage to recuperate from overwork but died during the journey. Thomas took over and not only maintained the reputation of the lenses his father had designed but he continually improved them and added new patterns. Among his principal inventions was the first practical telephoto lens (patented 1891) which he afterwards elaborated into many special forms for various purposes, a rapid landscape lens, a rectilinear landscape lens, some of the earliest rapid lenses made with lenses from Jena, Germany, and the Adon and Junior Adon telephoto lenses. He also invented the Naturalist's Camera for which he received the medal of the Royal Photographic Society. He also designed the Dallmeyer-Bergen lens, [Note 1] which was the prototype of the anachromatic lenses. [1] It was suggested by a painter, J.S. Bergheim, who wished for a lens which would give him correct drawing and soft definition without sacrificing the natural structure of the original. [2]
He was the author of a standard book on the subject of telephoto lenses, Telephotography (1899). [3] He served as president of the Royal Photographic Society in 1900-1903. [4]
He married Julia Fanny Thomas (died 26 September 1936), daughter of Charles Thomas Lt 54 Bengal Infantry, on 13 January 1886.
"The Dallmeyer-Bergen portrait lens is a simple telephoto composed of a single uncorrected lens, and the softness of definition is regulated by the diaphragm which is in front of all the glasses. It gives beautiful soft-focus effects without having to move the camera."— American Photography, Vol. 15, (1921) p.558
The following list comprises significant milestones in the development of photography technology.
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil. It is also known as the focal ratio, f-ratio, or f-stop, and is very important in photography. It is a dimensionless number that is a quantitative measure of lens speed; increasing the f-number is referred to as stopping down. The f-number is commonly indicated using a lower-case hooked f with the format f/N, where N is the f-number.
In optics, a circle of confusion (CoC) is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. It is also known as disk of confusion, circle of indistinctness, blur circle, or blur spot.
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
A telephoto lens, in photography and cinematography, is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus lens in a much shorter overall design. The angle of view and other effects of long-focus lenses are the same for telephoto lenses of the same specified focal length. Long-focal-length lenses are often informally referred to as telephoto lenses, although this is technically incorrect: a telephoto lens specifically incorporates the telephoto group.
Subminiature photography is photographic technologies and techniques working with film material smaller in size than 35mm film, such as 16mm, 9.5mm, 17mm, or 17.5mm films. It is distinct from photomicrography, photographing microscopic subjects with a camera which is not particularly small.
A zoom lens is a mechanical assembly of lens elements for which the focal length can be varied, as opposed to a fixed-focal-length (FFL) lens.
In film and photography, a prime lens is a fixed focal length photographic lens, typically with a maximum aperture from f2.8 to f1.2. The term can also mean the primary lens in a combination lens system. Confusion between these two meanings can occur without clarifying context. Alternate terms, such as primary focal length, fixed focal length, or FFL are sometimes used to avoid ambiguity.
John Henry Dallmeyer, Anglo-German optician, was born at Loxten, Westphalia, the son of a landowner.
Moritz von Rohr was an optical scientist at Carl Zeiss in Jena, Germany.
The following outline is provided as an overview of and topical guide to photography:
Nature photography is a wide range of photography taken outdoors and devoted to displaying natural elements such as landscapes, wildlife, plants, and close-ups of natural scenes and textures. Nature photography tends to put a stronger emphasis on the aesthetic value of the photo than other photography genres, such as photojournalism and documentary photography.
In photography, a rectilinear lens is a photographic lens that yields images where straight features, such as the edges of walls of buildings, appear with straight lines, as opposed to being curved. In other words, it is a lens with little or no barrel or pincushion distortion. At particularly wide angles, however, the rectilinear perspective will cause objects to appear increasingly stretched and enlarged as they near the edge of the frame. These types of lenses are often used to create forced perspective effects.
Tilted plane photography is a method of employing focus as a descriptive, narrative or symbolic artistic device. It is distinct from the more simple uses of selective focus which highlight or emphasise a single point in an image, create an atmospheric bokeh, or miniaturise an obliquely-viewed landscape. In this method the photographer is consciously using the camera to focus on several points in the image at once while de-focussing others, thus making conceptual connections between these points.
Landscape photography shows the spaces within the world, sometimes vast and unending, but other times microscopic. Landscape photographs typically capture the presence of nature but can also focus on man-made features or disturbances of landscapes. Landscape photography is done for a variety of reasons. Perhaps the most common is to recall a personal observation or experience while in the outdoors, especially when traveling. Others pursue it particularly as an outdoor lifestyle, to be involved with nature and the elements, some as an escape from the artificial world.
The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints that include cost, weight and materials. For many other optical devices such as telescopes, microscopes and theodolites where the visual image is observed but often not recorded the design can often be significantly simpler than is the case in a camera where every image is captured on film or image sensor and can be subject to detailed scrutiny at a later stage. Photographic lenses also include those used in enlargers and projectors.
The French firm Susse Frères manufactured a daguerreotype camera which was one of the first two photographic cameras ever sold to the public. The company was also engaged in the foundry business and owned a large foundry in Paris.
The invention of the camera in the early 19th century led to an array of lens designs intended for photography. The problems of photographic lens design, creating a lens for a task that would cover a large, flat image plane, were well known even before the invention of photography due to the development of lenses to work with the focal plane of the camera obscura.
Dallmeyer may refer to:
Harold Armytage Sanders, F.R.P.S. also known by the full name Harold Armytage Thomas Sanders, was father of World War I photographer Henry Armytage Bradley Sanders of New Zealand fame. As an optician he worked for W. Watson and Son. He went into business with Crowhurst with the business named Sanders and Crowhurst, and then was in business by himself as Sanders and Company.
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