Difference between revisions of "Heliar"
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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).<ref name=Greenleaf>Greenleaf, Allen R. (1950), ''Photographic Optics''. Macmillan, New York. pp80 & 83.</ref> 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.<ref name=USPat>[http://www.google.co.uk/patents?hl=en&lr=&vid=USPAT716035 US Patent 716035] of 1902, in the name of Carl Harting, for Voigtländer, at Google.</ref> 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. | 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).<ref name=Greenleaf>Greenleaf, Allen R. (1950), ''Photographic Optics''. Macmillan, New York. pp80 & 83.</ref> 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.<ref name=USPat>[http://www.google.co.uk/patents?hl=en&lr=&vid=USPAT716035 US Patent 716035] of 1902, in the name of Carl Harting, for Voigtländer, at Google.</ref> 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. | ||
Revision as of 18:09, 7 September 2011
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| Later Heliar on Voigtländer Bessa II image by Dusty Medusa (Image rights) |
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.
