I have a Summar and I love it.
Man, I can't find any of the images on the net (they're there somewhere - saw them not too long ago), but back in 1936 photographer Thomas D. McAvoy did a series of famous candids (and "candids") of Theodore Roosevelt using a Leica with a Summar lens which were brilliant and awe inspiring.
Here are some "letters to the editor" published in Time in 1936 which I did find (obviously) about the series, interesting in and of themselves:
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. . . The photographs of President Roosevelt taken by Thomas McAvoy [TIME, Feb. 25] were undoubtedly the best results that I have ever come across and I can understand only too well the technique that must have been necessary during their development to prevent halation, due to the windows in the background. My hat is off to this marvelous achievement in the advancement of photography. . . .
W. RADFORD BASCOME JR. St. Petersburg, Fla.
Sirs:
. . . As a doctor who pursues photography as a hobby, I am naturally curious about two or three technical details in connection with this striking piece of pictorial reporting. . . .
What type of miniature camera did Mr. McAvoy use, was the film panchromatic, how fast a lens was used and at what aperture?
Even serious amateurs have known for years that ammonia sensitization of motion picture film was practical, even if somewhat tricky, and I am amazed that no news photographer has tried it before.
C. D. ENFIELD, M. D. Louisville, Ky.
Cameraman McAvoy used a Leica camera with a Summar f2 lens, worked with the lens wide open at one-eighth second speed. His film was Du Pont Superior panchromatic, hypersensitized to half again its rated speed by exposing it to fumes of the strongest ammonia obtainable in a closed box for four minutes. Caution to novices: Film so treated should be used within eight hours. After that period it will not only lose its extra sensitivity, but may deteriorate below its original condition.—ED.
http://www.time.com/time/magazine/article/0,9171,883229-4,00.html