I wrote an article about the Carl Zeiss Jena Sonnars last year for "the.me" online Photographic Daily last year,
tried to capture some of the philosophy differences between Zeiss and Leica. John Naughten wrote the article "Why I love my Leica" in which he features a Robert Capa photograph taken on D-Day with a Zeiss Contax. I doubt the author realized that Capa had switched from Leica to Contax after the Spanish Civil War of 1936 because he found the Zeiss lenses to be superior to Leica lenses of the day. Capa used a pair Contax II with collapsible 5cm F2 Sonnars. The Leica equivalent of this lens is the 5cm F2 Summar, also collapsible. I have both lenses, and converted the collapsible Zeiss lens to Leica mount. Several Leica users had technicians do similar conversions in the 30s and 40s, the Zeiss Sonnars had higher contrast and better transmission than the Leica counterparts.
Today I took the pair of lenses out for a day at Burke Lake Park with my daughter. A great fun day, she has been going to this park since she was a month old. Riding the train and carousel is part of Summer.
First up, the Sonnar. Wide-Open at F2.
First shot is in the train, red lighting from the roof of the car. The Sonnar focuses to ~0.75m. I modified the mount.