Pierre Angénieux was the first to apply a retrofocus design to a wide-angle SLR lens with this very R1, achieving — for the first time on an SLR mount — a breakthrough in wide-angle lenses with a large maximum aperture.
The rendering of this lens is quite distinctive as well: whenever strong highlights enter the frame, contrast drops, bringing with it a faint, slightly bluish haze — almost as if the lens has a built-in "classic soft-focus" cinematic filter. It's very flattering for rendering skin tones in portraits. Once you get familiar with this lens's particular temperament, it can produce images with a truly distinctive character.
