Hi @alexs1320, those are pretty fantastic lenses (and I do remember reading about Stanley Kubrick's obsession to source the fastest possible lenses a long time ago). Thank you for the reminder!

While click through the link for the Zeiss f/0.7 lens it appears it was actually an f1 lens with a 0.7x reducer. I've seen a recent test with the Canon 85mm f1.2 with a 0.64x reducer, which yielded a 54mm f0.77, but unfortunately limited to Micro Four Thirds format. The problem seems image quality is not so good when you get to these really fast focal ratios.

Another problem - with digital cameras - is the light cone is coming in so steep that the microlenses in the camera sensor cannot properly channel the incoming light onto the pixel photosite - so there is a loss of light transmission as a result.