I conducted another entirely non-scientific test to see what the speed of lenses means for a bunch of lenses I own. What does it mean when a manufacturer claims that a lens has a maximum aperture of 1.2? I guess it means only what it means to our eyes.
So I took 8 lenses that are supposedly 'fast' and shot wide open with very dim light. You get an idea how the different lenses fare in low light, and how they fare in comparison to one another.
It is an unfair comparison in most cases. You can only compare a 50mm 1.4 against another 50mm 1.4. (which I did) But I also threw in my 25mm 1.4, just because it's a 1.4...
I lined up film lenses, TV lenses, FD, M42 and C-mount, all of them under f2.0
The one question that remains is: Is there an institution verifying claims of lens-speeds by manufacturers? (in other words: how do we know what we're paying for?)
Camera: Panasonic GH2
Music: ' I'm getting Ready' by Michael Kiwanuka