But yes they look pretty similar, but still with critical sharpness any amount of error, and it doesn't take much, could introduce softness.

I was just reading up on how Bryan does his crops because I'd like to so something similar for my own uses. As I'm sure you know it is pretty involved and he goes through a lot of effort to get some really clean results. Just one of the things he does is shoots remotely via computer monitor and focuses and refocused as much as 15 or 20 times! And then picks out the very best. I can see where just using the back of our cameras not being scientifically accurate or consistent enough to trust it 100%.

Or even the chart itself, it's a very finely printed one at 4000 DPI. Smooth texture. Large. Mounted on a 1/2" glass. Laser aligned ect. Definitely makes me apriciate the work that went into these crops.

Maybe your shots are representative, I can't really say. And you don't necessarily need to go to quite that far to know if your lens is sharp. But it sure does rule out a lot of variables.

Just food for thought. Your 2X ones are the only ones that seen quite soft to the point I do question them. I feel they are just soft enough where they are on the level or very slightly worse than the cropped image. And it would take very little to make it that way. Even just 10% sharper would make them slightly better than cropping. And then I could sleep at night.