Kubrick — via Bagelturf — shooting in candlelight using a modified Zeiss f/0.7 lens originally intended for spy satellites. I don’t think I saw the f/0.7, but I am pretty sure the f/1 Zeiss he had modified to mount onto a Mitchell camera was at the Kubrick exhibition in the ACMI (Melbourne) last year. There is an extract from American Cinematographer about it at Visual Memory (they also have a trove of additional Stanley Kubrick archives).
Current fast lenses include the Leica Noctilux-M 50mm f/1, VFX Supervisor Tommy Oshima has one… as do quite a few others… current version is $6k USD new. There is also the discontinued Canon EF 50mm f/1.0.