When Zeiss came out with the Super Speeds, Canon responded with the K-35's. They are very similar to Zeiss' prize creation.
I've shot a glam, bright and soft shoot with these lenses and they were absolutely perfect. Their low contrast, yet sharp glass were perfect. Even when you open it all the way, the slight bloom in the highlights and weird chromatic aberration are nice defects that add a lot of character to the image.
As said best by owner, Mark LaFleur:
"Canon K-35 Primes are some of the rarest and most prized cinema lenses available. They are unique in that they are vintage, super-speed, cinema lenses from the 1970s, which also happen to cover the Full Frame 35mm still format as well as RED's new 8K sensor. There are other prime lenses out there that cover Full Frame, but most are re-housed still lenses and no others have the beauty and character of K-35s. In 1977 Canon K-35s won the academy award for innovation in motion pictures, and they have been used recently on the films HER and AMERICAN HUSTLE."