Auteur: Marc .
Date: 22-08-2007 00:44
Effectivement c'est testé sur une 4x5" mais je pense qu'il a eu la décence de mesurer sur le format nominal 6x9 : "this is really a 6x9 format lens, but is included here because I tested it using a 4x5 camera".
Pour les autres Ektars, les sources varient. Ici
http://www.largeformatphotography.info/classic-experts.html
Michael Liczbanski écrit :
"Kodak Ektar 3.5/100 (for Kodak Medalist)
5 elements in 3 groups, covers 2 1/4 x 3 1/4 (and 6.5x9 cm)
Kodak Ektar 3.7/105
4 elements in 3 groups, covers 2 1/4 x 3 1/4
*** A very good lens, also used on the Precision enlarger. Sharp and contrasty."
Et ici :
http://www.prairienet.org/b-wallen/BN_Photo/LostSites_MonaghanEktar.htm
Richard Knoppow écrit :
"My information (from the Kodak Data Book _Kodak Lenses, Shutters, and Portra Lenses_, 3rd ed. 1948, and several other sources) indicates that the 105mm f/3.7 Ektar is a 5-element, 3-group Heliar type like the 100mm f/3.5 Medalist II lens."
et aussi :
"One note on the 105mm f3.7 Ektar... It is easily confused with the 107mm f3.7 Kodak Anastigmat which I believe was prewar, and I think it was a 4 element lens rather than a 5 element Heliar copy. Kodak put out a booklet called, I believe, Kodak lenses & shutters or something like that. Showed the formulas (formulae?) for most of the Ektars"
et dans la même page G. Lehrer écrit :
"...This effect was used by the lens designers of Eastman Kodak in their design of at least three Ektars: the f2.8 80mm as used in the first Hasselblad, f3.5 100mm as used in the Medalist, and f3.7 105mm as used in the Miniature Speed Graphic. These three lenses have absolutely identical elements, they ONLY differ in the spacing of the groups. This was shown to me by Dr Kingslake in one of the many seminars he gave. These were all superb lenses,and could hold their own against most modern lenses."
etc...
Je pencherais pour l'avis de Knoppow, c'est lui l'expert je crois...
Ce serait un 5 lentilles / Heliar dans les deux cas et expliquerait les performances.
Pas vu de mention de 6 lentilles pour ces deux Ektars.
Désolé, le message est un peu long.
Marc . (un autre...)
Marc . (un autre... MkII ?)
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