I'm going to play devils advocate and answer some of my own questions in response.
Devil: "how do you quantify that the claim "X glass is better than Y glass" is "absolute and utter nonsense.""
Bill: I'm going to go out on a limb here and say that the answer is because optical glass is a formula - a combination of various earth elements (e.g. Crown glass = quartz (SiO2): ca. 73 %, sodium oxide (Na2O): ca. 5 %, potassium oxide (K2O): ca. 17 %, calcium oxide (CaO): ca. 3 %, aluminium oxide (Al2O3): ca. 2 %) and any of the "good" glass manufacturers should be able to create the same "type" of glass given the same quality of product, but I also understand that there are different levels of impurities that can reside in the source material, so as long as the same level of impurities is maintained then the resulting glass should be the same.
To my everlasting shame, I am guilty of having glass bias. At times I have promoted "German" glass above "Japanese" glass, but only because of my experience having used many scopes of both European and Japanese origin. In the past, the very best scopes from an optical perspective were Schmidt & Bender, Hensoldt, Swarovski, Premier et al; all happened to use "German" glass while the best scopes from Vortex, Nightforce, Bushnell Elite et al all happened to use "Japanese" glass and every time I compared the "best" from Germany to the "best" from Japan I found the German sourced scope to be superior. Thus the bias was created in my mind "German glass is better than Japanese glass". The first time I ever saw Japanese glass that came "close" to what I saw from the German glass was from March, outside of some of the issues inherent to their 8x FFP design the "pop" (resolution, contrast, color, CA) was very similar to what I saw out of my European scopes which made me realize that there may be more than meets the eye
Devil: "But what about all the light transmission numbers?"
Bill: Light transmission is largely a marketing ploy, Schmidt & Bender may advertise 96% for their Ultra Bright 4-16x56, but compared to Schmidt PM II 5-25 which has a light transmission rating of 90%, if you set both scopes to 12x will you actually "see" more light from the Ultra Bright. In a blind test I'd venture to say you'd be hard pressed to discern a difference and that's because of our eyes ability to compensate extremely well, so while an optical instrument used to measure these numbers may be able to pick up the difference that is not to say our eye can, again, all things being equal because if you pickup a "cheap" 5-25 scope that may have similar specs, the image you see will be vastly different due to the quality of the glass and coatings. When we hear claims like, "I was able to see 15 minutes longer past sunset with Scope X" I find these claims to be somewhat disingenuous because how did the user make this determination, were they in a controlled environment with both scopes side by side etc., or was their "perception" that they could see longer with scope X. And here is the rub, our "perceptions" have power over reality in many situations. Think of the magician, they are able to alter your perception through slight of hand and convince you to think you saw something you actually did not - I believe similar things happen when we look through scopes which is why we'll often see a group of shooters saying scope X is better than scope Y and another set saying the exact opposite.
Devil: "Only scopes using Schott HT glass have high transmission right?"
Bill: Again, go to my first paragraph above, there is a formula for glass and while there may be tweaks to this formula it is still a formula. Also, light transmission often is a result of the multi-coating(s) used which are themselves a formula. Keep in mind that many manufacturers like to keep their formula's secret, like Grandma's secret spaghetti sauce recipe handed down over the generations. But that's not to say that just because Schott has HT (High Transmission) glass, that other glass manufacturers can't create their own HT glass.
Maybe to those who don't know you ILya, but for those that do, your voice carries a lot of weight. Most of us do not have the experience that you have working with optics and lenses and everything in between.
Devil: "But the marketing materials say this or that"
Bill: What is the goal of Marketing, to bring awareness to a product in order to get sales. We've all seen the clever slogans, for those of you who are old, when I say the phrase "It takes a lickin' but keeps on..." what comes to mind? Anyone who's seen the old Timex commercials will immediately recognize this - clever marketing with a catchy phrase to get you to believe that Timex watches can withstand a lot of abuse. Think of what Nightforce did with their video a few years ago driving a large metal spike into some wood with the objective bell of one of their scopes, then mount it back up and it shoots straight. Does that mean other scopes couldn't do the same, certainly not, but that was clever marketing from NF to show how durable their scopes are.
Devil: "So why don't we see scopes on par with German glassed scopes coming from other areas?"
Bill: To ILya's point - "made for a specific purpose, to a specific budget". Over the past 7 years we have seen continual improvements from scopes coming from Japan (and improvements from Philippines and China as well) due to modern manufacturing methods and advancements in computer aided designs. March stands out as one of the Japanese manufacturer's who appear to be able to challenge the traditional European alpha class designation IMO. I have high hopes for what is to come from this manufacturer, but even Nightforce has shown improvement (look at the many claims the 7-35 "looks" better than the 5-25), Bushnell with their new ED Prime glass, Burris with the new XTR III showing great improvement over the XTR II and the many new designs from LOW that we are seeing pop up left and right these days. Not only that but Vortex has challenged with their AMG 6-24 scope, showing that even American sourced glass can prove to be a worthy competitor. So while the "best of the best" seems to have come from Europe I think we will begin to see the Japanese encroach further and further into the alpha class market.
What this all means for us is that better and better scopes are hitting the market and we shouldn't be worrying so much about where this is made or where that is made, but truly look to the quality of any given scope and judge it based on the merits of what it has to offer you and for your style of shooting.
