Grant and Paul, you are very kind, I am not an expert in the soft stuff, however I will follow what you tell me tomorrow. I just hope I don’t do any damage to my system.
However, I see that the problem is not limited only to the jpg format I use, which gives little information. Certainly there remains the problem of reducing the PVs at the same shooting time. I enclose another graph that I constructed just today. In it, the PVs are shown as a function of the lens area (abscissa at the bottom) and the relative aperture ratio shown at the top, and for various ISOs. It is comforting that there is proportionality between PV variations for a given number of ISOs. It is certain then that PVs are a function of at least 2 variables: ISO and shutter speed. The mathematical function seems to be quite difficult to handle. I am looking for a good way to find it and then handle it as easily as possible.
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