Cameron,
I have been following this thread since my original post. I read your original comments and the subsequent response to the private message (me thinks I know who it was from though I did not know he purchased the Swarovisions...it has been some time since the two of us got together.
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I understand your stance on the issue of CA and the general public. You are right actually. Most folks pick up a binocular and notice handling first, then image quality followed by focusing speed and tension. They notice how bright the image and how sharp the image is...how wide the field of view is and how easy it is to follow a bird in flight. Not many individuals in the general public even know what CA is or how to identify it. If you placed two identical binoculars side by side (one with ED glass and one without) then joe consumer may notice that one is slightly sharper with more vibrant colors but he probably would not be able to tell you why.
I have often read on various forums that the benefit of ED/FL glass in binoculars is overstated, especially in "low power" instruments in the 7x-10x range. I could not disagree more. For anyone that has spent a great deal of time behind optics the benefits are obvious. Images look so much more lifelike...crisper, brighter and more colorful. Being able to see the finest details seems much easier in an ED glass binocular. One must assume that it is the result of the decreased level of CA in the image.
Sure, manufacturers have taken advantage of the momentum that ED glass has created. You can see ED glass models in just about every price range (from $150 all the way up to the $2500 models). Is it just marketing hype? Certainly not and I know you would agree with me on that point. The benefits are real and I do applaud the manufacturers for addressing one area of optical deficiency that has existed in one form or another since binoculars were invented.
Just my two cents.
Frank,
I'll see your two cents and raise you two more, but with one qualification, which I will address at the end of this post.
I've had this debate with none other than Professor EDz. You think someone with "ED" in his name would appreciate the benefits of "ED" glass.
He said what you quoted above, that the benefits of ED glass in "low power" instruments is "overstated".
Of course, he mostly uses bins for stargazing, so the benefit for that use is not as obvious unless you're looking at the moon or one of the brighter planets or brightest stars. "Faint fuzzies" have too little contrast against the background sky, particularly under bright suburban skies for ED glass to make a stark difference.
But for birding, the difference is quite stark, at least for those who are sensitive to CA. Not only the lower CA in high contrast situations but also the richer, more vibrant colors and sharper and higher contrast images. Of course, the top bananas, which already have excellent color saturation and contrast, those benefits may not be as noticeable as the better CA control.
For example, in comparing the 8x32 HG to the 10x42 EDG, colors looked as saturated and the contrast was as good in the HG as the EDG despite the greater CA in the HG.
I'm opening a can o' worms here, but I also thought the ED glass in the EDG I wasn't as good (or the end result of the entire optical train wasn't as good) as the Celestron 10x50 ED porros I had, which showed no CA on axis and very little half way out. The EDG showed CA just off axis against a high contrast background, and CA was more obvious than the Celestron at half way out.
One reviewer even noted some CA in the 7x42 EDG. I saw no CA in the 7x36 ED on axis and only minimally half way out, not even much near the edge. I don't see any on axis in old Nikon 7x35 porros either.
So I'm a bit puzzled by this less than optimal CA control in the EDG and wondering if the 10x sample I tried and the 7x42 reviewed were anomalies.
I have noted repeatedly that before the addition of ED glass, I saw more CA in the roofs I tried than I did the same configuration porros. Henry suggested that the internal focusing element may play a part in this, but I don't think that's ever been confirmed. Presumably the 7x ED2 has internal focus like the 7x EDG, but there are differences in some bins with positive and negative lenses used as the focuser lens, which may be a factor. Someone mentioned this a while back so I thought it was worth repeating here, but elkcub, please don't ask me to dig out that reference!
The reports of greater CA in bins around the mid to late 1990s can't be ignored, and I don't believe the spike in CA reports were due to greater awareness of the issue from the reviews of Stephen Ingraham and others, as someone suggested. By the time the Leica Ultravid BR and the Swaro EL was introduced, the lead free glass should have been as good as lead glass even if the earliest attempts at lead free glass were less than optimal, and nobody knows if any of that glass was ever used in binoculars so no point going there again.
Whatever the cause, ED glass, which was used in porros nearly 20 years ago, has now become the new standard in roofs.
Something tangible was going on with pre-ED roofs in terms of an increase in CA, and I believe that ED glass was introduced to address this problem, but now it's become a "fashion trend" to the point where ED glass is becoming ubiquitous in roofs today, now even in a compact (8x and 10x25 Alpen Wings EDs).
Being sensitive to CA and enjoying vivid colors and high contrast, I think that's a good trend. However, I'd like to see the optics companies post the type of ED glass use, so we know whether or not we're comparing apples to apples since not all ED glasses are created equal (they are not covered under the US Constitution
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Here's my caveat, hinted at in the start of this post. Even with that (20-years-in-the-making) "innovation," the overall optical quality of the bin still trumps whether or not it has ED glass.
For example, while I really liked the sharp and "clean" images in the center of the 7x36 ED2, the lower distortions off axis in my EII and SE made me chose them over the ED2 roofs.
So while ED glass can be an important upgrade to a binocular design, in and of itself, it is only one component that produces the "better view desired".
Brock