- Plasmat lens
The Plasmat lens is a widely used and long-established lens type, especially common in
large format photography. It provides high correction of aberrations with a moderate maximumaperture (e.g. f/|5.6|link=yes).In its most basic form it is symmetrical and consists of two cemented groups of three lenses each. The innermost element in each group is a positive meniscus, the outermost is biconvex, and there is a biconcave element between them.
The Plasmat lens is made in many variants, e.g. departing from exact symmetry, adding a lens to one or both groups, or separating the innermost or outermost element from the rest of the group.
Standard lenses for large format cameras are generally of the Plasmat type, as are many
macro lens es. Convertible lenses for large format photography often consist of Plasmat cells.ee also
*
Large format lens References
* [http://books.google.co.jp/books?id=OJrJrEJ-r9QC&dq=%22a+history+of+the+photographic+lens%22+rudolf+kingslake&pg=PP1&ots=YY-kaKy5aA&sig=WOBds_DaDP9DscZNJcU4Jke8KYc&hl=ja&prev=http://www.google.co.jp/search?q=%22A+History+of+the+Photographic+Lens%22,+Rudolf+Kingslake&ie=utf-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&sa=X&oi=print&ct=title&cad=one-book-with-thumbnail#PPA95,M1 "A History of the Photographic Lens"] Rudolf Kingslake p. 95 Retrieved from books.google.co.jp
February 20 ,2008
*Sidney F. Ray, "Applied Photographic Optics", London and Boston: Focal Press, 1988, ISBN-10: 0-240-51226-X. Also later (corrected) editions.
Wikimedia Foundation. 2010.
