----- Original Message ----- From: "Emmanuel Bigler" <Emmanuel.Bigler@xxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx> Sent: Thursday, January 15, 2009 12:41 AMSubject: [rollei_list] Re: OT: A Sonnar 1.5/50 72 years old + Images with the rolleiflex original
This one was taken using the lens widest f stop: 1.5 at 1/25 sec... This one was taken using a wide f stop too, but smaller than 1.5 and fast shutter speed (perhaps 1/500):Superb images, Carlos ! [OFF-TOPIC BUT SOMEWHAT RELATED TO VINTAGE ROLLEI CAMERAS]This is a good answer to people insisting on having the last multi-coated lenses "because the older ones are not good for color" ;-)There is a nice collection of kodachromes in 4x5" format taken in the USA just before WWW-II or during WW-II, my understanding is that none of the lenses in use were coated
Most, if not all, of the images at Shorpy come from the Library of Congress archives and are available on line. The Shorpy images have been adjusted, at least to some extent. The LOC images are available as TIFF's and are _very_ large. Kodak began coating quite early. A few premium Kodak lenses had soft coatings on internal surfaces by about 1940. These included the Eastman Ektar series (later renamed the Kodak Commercial Ektar when hard coatings were added) and the lenses for the Ektra camera and, I believe, the lens in the first Medalist camera (the Medalist II had hard coated lenses). Many, but not all, of the 4x5 images in the Kodachrome collection were taken with Speed Graphics, probably most equipped with Kodak Ektars. I have an early 127mm, f/4.7 Ektar (date code 1940) which is uncoated and shows no sign of ever having internal coatings. It has a noticable ghost image of very bright objects in the image field, an effect which does not occur in the later, coated version. The Sonnar was designed with flare in mind. It is essentially an elaborated Triplet with only six glass-air surfaces. Cemented surfaces have much closer matching of index of refraction than glass to air so have little reflection and cause very little flare. Before good coatings became available some very good lens designs went begging because they had too many glass/air surfaces and too much flare. The use of designs with a muntiplicity of cemented surfaces to avoid glass/air surfaces stopped almost immediately when coatings became available.
-- Richard Knoppow Los Angeles, CA, USAdickburk@xxxxxxxxxxxxx
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