Difference between revisions of "Heliar"
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Voigtländer used the lens like the Tessar; it was the lens fitted to most of the company's high-specification cameras for many years. | Voigtländer used the lens like the Tessar; it was the lens fitted to most of the company's high-specification cameras for many years. | ||
| − | The original Heliar design was an f/4.5 lens; f/3.5 versions of the same optical design were offered fairly soon after (''alongside'' the f/4.5 | + | The original Heliar design was an f/4.5 lens; f/3.5 versions of the same optical design were offered fairly soon after (''alongside'' the f/4.5). The wider-aperture lens has a slightly narrower field of view.<ref name=Cat1927>A [http://www.cameraeccentric.com/html/info/voigtlander_1.html Voigtländer catalogue] of 1927, at [http://www.cameraeccentric.com/ Camera Eccentric] shows both the f/4.5 and f/3.5 lenses. The angle of view of the f/3.5 lens is given as about 50°; that of the f/4.5 is given as about 58° (up to focal length of 24 cm; for some reason (perhaps simply bellows extension) it is given as 45° beyond that.</ref>). |
Revision as of 12:33, 31 August 2011
The Heliar is a lens designed and made by Voigtländer. It was patented just after the turn of the 20th century in Germany (1901), Britain (1901) and the USA (1902).[1] It comprises five glass elements: the front group is a cemented doublet of positive power, composed of a crown glass element at the front, cemented to a flint glass; there is a central, diverging element of a different crown glass, and the rear group is another cemented doublet, identical to the front group.[2] Thus it seems like a development of a Tessar design, with the front group divided to allow more corrections; however, the Heliar clearly predates the Tessar by about a year.
Voigtländer used the lens like the Tessar; it was the lens fitted to most of the company's high-specification cameras for many years.
The original Heliar design was an f/4.5 lens; f/3.5 versions of the same optical design were offered fairly soon after (alongside the f/4.5). The wider-aperture lens has a slightly narrower field of view.[3]).
Notes
- ↑ Greenleaf, Allen R. (1950), Photographic Optics. Macmillan, New York. pp80 & 83.
- ↑ US Patent 716035 of 1902, in the name of Carl Harting, for Voigtländer, at Google.
- ↑ A Voigtländer catalogue of 1927, at Camera Eccentric shows both the f/4.5 and f/3.5 lenses. The angle of view of the f/3.5 lens is given as about 50°; that of the f/4.5 is given as about 58° (up to focal length of 24 cm; for some reason (perhaps simply bellows extension) it is given as 45° beyond that.
