Maximum aperture values in third and half stops can be tricky to compare, so I’ve made a table to aid the task. Below F1.0 it gets a bit trickier still, so don’t take it as gospel (and it’s subject to amendment), but you’re unlikely to come across that many in regular production. The Nikon Noct Nikkor and Leica Noctilux, for example, are both F0.95, which as you’ll see, is 1/3 stop ‘faster’ than F1.0 and 1 1/3 stop faster than F1.4. Against an F1.2, it’s + 5/6 stop faster or +8.33 Ev brighter, so it’s quite an advantage in low light. Interestingly, if you’re a film buff, Kubrick’s Zeiss Planar…