Miles,
I set them all on 6x, and since it's rare to find a variable that doesn't include 6x with less than 36mm objective. Setting the scopes on 6x results in an exit pupil of at least 6mm, and usually larger. Supposedly the "average" human eye's pupil expands to 7mm in darkness, but I've found 6mm more like it in any sort of hunting light, so a 6mm exit pupil provides all the light our eye can use.
Magnification also affects perceived brightness, essentially due to placing the object closer to the shooter, but I designed the test to be as close as possible to a pure comparison of optical quality.
The black and white chart also eliminates color from the equation, making the test just for brightness and sharpness. Individual perception of color varies, often considerably, and can make a specific scope appear brighter to one person than another.
Hi JB
What actual parameters are you testing? "Sharpness" I'm guessing is resolving lines, or something similar, is that right? What about "brightness"? How do you measure that?
Have you done any ranking of scopes measured at the maximum magnification they can reach? Or the maximum at which they still have at least 6mm exit pupil? It'd be interesting to have some objective data showing not only how how various scopes compare with each other at 6x, but also how they compare with, say 4x scopes, 8x and variables.
