Just a quick answer about stops/EV values and lux, etc.
It's really very simple in that each stop is exactly 1/2 or double the light output.
For example: if you've got a reading of 200lux or cdm, one stop reduction would equal 100lux, as in 1/2 the original. One stop increase is therefore 400lux. So, f2.8 is allowing exactly 1/2 the light to get to a sensor/film as compared with f2.0.
That's why it's a very easy system to get one's head around. And therefore, f4.0 is exactly 1/4 the amount of light as compared to f2.0.
Hope this helps somewhat. Btw, what CCT (correlated colour temp) is your light booth reading as per your i1pro evaluation? And what program did you use to obtain said readings/evaluation? Did you use i1share or say, BabelColor PatchTool/CT&A or something else altogether?
Also, what Rev. letter is your i1pro, as in Rev. B, Rev. D, ect?
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