I went down this rabbithole, deeper than makes sense some years ago. For just sporting rifle scope evaluation, I think the 1951 USAF is as good as any. I did discover that you don't want to print it on anything more reflective than flat white recycled paper. Another thing I 'discovered'...the most repeatable results occurred when I placed the target at optimum parallax distance (?). When I evaluated 2 scopes that seemed of equal resolution, another thing I 'discovered', was that the front page of a newspaper with varying print sizes, placed at optimum parallax distance was a good tie breaker. There is a chart, made up of radial bars in the general shape of an Iron Cross, and it creates so much eyestrain that I would get a splitting headache in 3 minutes or less. I never had any real high end optics to test, but I was amazed to discover that old brand name and Jap optics of the 1970's were not all that bad, at least in the one category of clarity in good light.
