[JJ_SO]

Optically a lens can be reduced to test results though, just not ones used by photographers.  Interferometry is the only method I know of that reduces a lens to pure aberrations in a way that mimics design as well.  In design you see a transverse ray plot.  The focusing error of the ray is aberration.  Different aberrations have different focusing errors throughout the pupil.  Here is spherical aberration:

...

 

You can even compute the coefficients of the aberrations in a merit function for the real lens through it, or the coefficients, normalization radius, etc, for aspheres. 

 

My beef with lenscore's test is that any aberrations in their mysterious optic between the lens and sensor confound the results unless the optic is diffraction limited at an aperture faster than the lens being tested. 

 

One can compute an already computed lens, but what does that say about it's manufacturing quality? How does the analysis program gets it's formulas and coefficients? If not by originally long rows of experiments? Why don't you doubt them not a bit, too? 

 

I have no idea nor experience with interferometry and the same goes for LenScore's testing method. I also can read the theory of an optical bench (also not to your taste, I guess  ) but I haven't seen one in the flesh nor tried to work with one, beware.

 

I guess (!) they use a big sensor and enlarge the picture given by the lens, sort of the way its' done by speed boosters on µ4/3 - and there the speed booster doesn't take away image quality. Of course you can doubt this optical adapter as you can doubt anything else. I just ask what's the point of spending lots of money in it and go public with the results? Only confusing amateurs or provoking discussion in their forums?

 

You realize, Scythels, we're moving very far away from the original question?

 

By searching for a link of how this speed boosting works (and I still guess, LenScore uses kind of the same device, just for FF lenses), I found also one about a comparison between the Sigma 24-105 and the Canon 24-105, together with a chart about both's sample variation: http://www.lensrentals.com/blog/2014/03/...comparison

 

The link for speedboosting by metabone magic from Roger Cigalla. And I see my memories were completely false, actually speed boosting is the opposite of what I think happening at LenScore. Anyway, as long as they use there "resolution and more" checking machine the same way on each lens (and they do it with kind of automated process) there are at least comparable results.