I agree with the sentiment ... ED (and HD and XD and ....) have become marketing terms. But they do help in a good design.
Which "poor" ED bins were you thinking about, Tom?[/QUOTE
Telling names?
Skating on thin ice, isn't it?
Well, I have recently had a chance to play with ... not quite all but with many at an exhibition.
I tested the Pentax DCF ED, for example. Specifically labelled as ED it had stronger lateral chromatic aberration at the periphery of the fov than for example a Zeiss Conquest which does not boast ED.
then there are the Leica Trinovids which had some sort of ED glass 10 years ago, but Leica never made a big story out of it.
One ED bin which was nice colour-wise but which I disliked for other reasons was the Swift Audubon ED (Porro).
What I mean to say (or meant to say) is that "ED" alone does not make a perfect binocular - sometimes not even a really good one.
If it is part of the package, it can contribute to a good result, but it is only one chapter in a book. In the end we are not buying an ED lens but a whole bino.
So my message was: do not get carried away by "ED", or in fact any other fancy label.
Even if it does not say so explicitly or boast any other "virtue" (real or imaginary), some fine instruments out there have a personality that is best described as "distinguished understatement" (Rambo in a three-piece suit with a bowler hat, sipping green tea, so to speak
)
Tom