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Message: <blockquote data-quote="elkcub" data-source="post: 3399263" data-attributes="member: 14473">The procedure involves Henry's instrument-aided acuity.  Assuming his acuity remains constant, the numbers reflect the relative resolutions of the instruments.  Under the same test conditions, you or I might get different numbers, although the order would probably remain the same.  That's what I believe.That's what you believe in the perceptual domain.  No standard chart was used, and no one else has any basis for knowing what you consider to be 'seeing fine detail.' Whatever "better" refers to, the edge of the Habicht is further from the center than the SE's.  The statement, therefore, is meaningless unless this is corrected.  A way to do it would be to mask the Habicht's FOV to match the SE's, and then make comparisons. True, keeping in mind that the shape of the distribution controls color contrast of the image.   Henry is referencing the image domain; you are referencing the perceptual domain.  Unfortunately, there isn't a psycho-physical function that maps directly from one to the other.  In the past I've owned both instruments, but did not come away with the same perceptions you have.  Be that as it may, I for one have no basis for questioning the validity of Henry's relative resolution measurements.Ed</blockquote>