I was thinking the same thing yesterday when I was comparing my Maven B3 6x30 to my Meopta B1.1 8x32 .... the Maven seemed to provide a larger magnification than 6x. To be honest, I would not even know how to actually test an optical instrument for its magnification accuracy. I wonder if ones personal eye characteristics as well as our age has anything to do with this after our brain interprets the view it receives.
Gcole,
First, I am not an expert. This perception of magnification probably does have a lot to do with individual physiological characteristics, age, accommodation, et.cet., as Troubadour Lee explained to me in response to an earlier question on the subject. I asked because when I first got the Kowa 6.5x32 just using it in rotation but not directly comparing to other 6, 6.5 and 7X, the Kowa magnification seemed closer to 7 than other 6.5's and definitely greater than 6X.
Then Gjs published his findings, including the 6x, not 6.5x of the Kowa. I assumed he was right and so did a direct comparison with seven or eight other 6, 6.5 and 7x bins to try to understand why or how the Kowa appeared to me greater than 6 and even greater than 6.5. This only resulted in more confusion because it sometimes appeared the Kowa was either 6, 6.5 or 6.5+. While I can't recall which, this impression of more or less than 6.5X seemed to definitely change depending on whether my wife and I were looking at natural or man made objects to compare.
Then WJC/Bill posted an explanation with a couple of helpful pictures (in a different thread- can't find it now) illustrating that when comparing two bins of identical x, the one with a wider FOV could create an impression of greater magnification.
All this helps me understand my subjective experience in the 6x to 7x range, although it may not directly address your perception/comparison of a 6x with an 8x.
Mike