"f0.95 is faster than f1.0"...An air of silence...because no lens manufacturer, in their right mind, will come out and say that! They will just print that on their latest super duper chunk of glass and let the reviewers and public awe takeover. Eventually, and the lensmaker knows this, everyone of those fast lens enthusiasts(and who isn't...) out there will gravitate towards their f0.95 lens rather.
So how much faster is f0.95 than f1.0 and also why is it that Canon and Nikon shows f1.2 on their fast lenses and cameras while Sony uses f1.3 rather and all of them deemed to be 1/3 stop faster than f1.4?
Figure 1 |
Of course a mathematician would have noted the inconsistencies in the aperture values of accuracy to 1 decimal place for aperture values slower than f1.0 and to 2 decimal places for values faster than f1.0. This, the optics theory physicist would argue, is due to an ever increasing rate of the entrance pupil area change(larger) as values of aperture drops below f1.0 towards the theoretical limit of f0.50.
At f1.2, entrance pupil area is 17% larger than that at f1.3, about one sixth of a stop and yet both are deemed equal or of no noticeable nor consequential difference(for all intents and purposes...) to the modern digital sensors of today.
Now comes the lamer, f0.95 and f1.0 only differs by 10, well ok, 11% in entrance pupil area, effectively one tenth of a stop. This is where when you see f0.95, it really begs to be no different from f1.0.
Thank you Canon, Voigtländer and Leica as well as clever rebranders of security camera lenses for making this blog post possible. ;-)