So here is what I think to know from reading around on AVS:-) the field of view is an imaginary circle and the size of this circle differs between meters. Put the meter further away from the screen, and the size of the circle increases. Thus, putting the above mentioned meters the same distance from the screen, will make the i1 display pro read a larger portion of the screen area than the i1 pro 2.
The primary reason the FOV needs to match for meter profiling, is display uniformity variance. Displaying, for instance, the pattern for full read on a LCD can show that the delta E is not constant over the entire screen surface. Meter profiling is meant correct the measurement error in the colorimeter so that it will measure the same as the more accurate spectrophotometer. The measurement error could be wrong (influenced by display variance) if both meters are measuring a different portion of the screen.
Now then, on my plasma moving the i1 display pro further away (1-15 cm) or closer (as close as possible = contact mode) does not change the x,y readings for red at 75% stimulus, 100% saturation significantly(I tried green and yellow too). Sure it fluctuates with 0.003 at the most but I understand this is within repeatability limits. What *does* fluctuate harder is the light reading (Y).
So, what if we would exclude Y from the correction matrix seeing colorimeters should already be better at reading it anyway? And why does Y vary harder?
My gear: Panasonic TH-42PF11EK pro plasma display + TX-P55VT60E -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer