Okay, all this debate over the "true" f-stop of a lens has me scratching my head.
Since metering is through the lens and presumably the exposure selected by the camera is going to reflect the actual light hitting the meter, what's the real world impact here?
Yes, I get that a mis-marked lens means that your f4 lens won't have as great of a light gathering power if it is really an f4.5 lens, but unless you are shooting wide open, what's the practical effect. Your images will still be properly exposed.
Now, obviously if you bought a lens thinking it was an f2.8 and it was really an f4.5 that would be some serious fraud going on.
While were on the topic, aren't there also some standards that must be met. After all, ISO stands for the International Order for Standardization.