I think the big takeaway from it is this paragraph:
This is why the opinions about glass quality you read are often worthless, and why you get completely opposite reviews about the glass quality of a particular scope. Most will get behind two scope, only adjust the parallax knob and then compare them. If they haven't adjusted the ocular, it can affect the image quality and even the magnification. The Precision Rifle Blog guy made this mistake and said that an S&B 3-27x really only went to 22x. The scope was sent to S&B, and they found that was incorrect, that he had not adjusted the ocular correctly. This is why his whole section on glass quality should be taken with a grain of salt. The scopes were not being adjusted properly for each user. Was the the glass quality of one really better than the other, or was one just not adjusted properly? Maybe one is more forgiving than the other in terms of adjustment, we really don't know...
Also, if you really want to compare two scopes evenly, the erector needs to be centered. The clearest part of a lens is it's center, and your eye is naturally drawn to the center of the crosshair. The further you move ways from the center of a lens, the more things like chromatic aberration start to show up. If one scope is close to the center, it will likely have a better image than one that is close to its limits. That isn't a fair comparison.
Very good points and goes to show that not everyone that does reviews KNOWS how to set up a scope.
One of the biggest flaws I see in scope comparison is the object they are viewing. Many will use a standard object with little distinct features. Say they are looking at a car... do you see the car? Yep... nothing really to differentiate cause anyone is going to see the car.
What I use is a hand railing and chimney on homes over 1000yds away. There is no doubt that the are plenty of straight equally spaced lines and everyone understands what they are looking at.
But in comparing many scopes, my question is always... "what do you actually see?" I have yet to look through a scope that couldn't make out the shape of the chimney or the white lines of the rail.
Where most fail is being able to resolve the grid of these objects. To actually resolve and differentiate the detail that make up these patterns. Some will even bend the image so the objects are curved... which of course they are not.
So many scopes will see the rectangle that is the chimney, with blotches of colour that are the bricks. If it is a scope, odds are you can see this.
Scopes that many call very good glass, will show the grid that is the grout lines but they are faint. There will be the blotches which are the bricks, then a line, then a blotch. In this class, better scopes will give clear colour distinctions from brick to brick and within the brick itself.
Even better will clearly resolve the grout lines so they are sharp and distinct. You can see where they start, end and even if they do not line up with the next line. When highlighted with good light, each brick is clearly resolved in colour with the typical pattern easy to see.
Top tier glass under clear air and good lighting... you can see the texture and shadows in the grout line. Texture, lumps and bumps of the brick.
What do you see?
Jerry