I will withhold any real comment on that particular test until I have seen at least two more tests of other brands by the same author.
I too, of course, was surprised, and disappointed, by the results. I wasn't surprised that he found variation from sample to sample, but I was surprised at the overall low performance.
I always tell people that you pay for the specified performance, and you should get that...but that does not mean the certain samples won't exceed specifications. And who is going to complain if they get the "cherry" in the batch. At the same time, you can't complain if you don't get the cherry...as long as your sample preforms up to specifications. That kind of variation has been my experience of all the top brands over 20 years and more of testing. I expect that kind of variation.
And, since the low performance in the test is NOT my experience of Diascopes, and I do look through a lot of them in the course of my work, I'd like to see what kind of results he gets with other brands.
Finally, let me say that we do take all such reports from the field seriously, and review them, and, when they prove to have good basis in reality, as they rarely do, we take appropriate action.
S. Ingraham