Hi--
>I don't know how you get the above data. I would love to know...
>Furthermore, I have no precise equipment to measure. What I have is
>slide film and the same developing lab. To my F3, Fuji Velvia is at
>best if rate at ASA / ISO 50. But to my F90, the same film should be
>rated at + 2/3 compensation. While Fuji Sensia 200, F90 works best at
>rate 200 ISO, but F3 overexposed the film very much. The images look
>washed out. When I try another lab, the result is totally different.
>All I know is that My F3 expose about 2/3 stop more that my F90.
I use two light sources in my darkroom - one low level, the other high.
I relate them to meters and films that are known (so I have a reference).
It sounds like you need to find a reliable lab so the film variable is
reduced - then you can work on the meters. It sounds like your N90 may
be correct and the F3 needs "-1/3" compensation (maybe!). I do not
recommend using Velvia as a reference film, since its speed varies from
about 40 to 64, depending on subject color! (40-"45" is about right,
unless there is a lot of green, or you shoot close-ups of flowers or
other bright-colored subjects).
>I learned from magazine that many pros love to use Velvia at ISO 40 or
>using it at ISO 100 and pushing one stops.
>
>What I disagree is the term inconsistent. It seems to me that those
>cameras are consistently biased some what. It is our best to know
>difference in direction.
>
>Keep in touch, I would love to hear more from you. I guest you must
>have so much experience in photography.
>
>Edmond
>
Hope this helps. David Ruether