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Message: <blockquote data-quote="elkcub" data-source="post: 1863786" data-attributes="member: 14473">Hey Henry,You might reread a few of the earlier posts, since the Audubon collector's issue is not design differences between the eyepieces, but differences between MC and FMC coatings.  I may not have made it clear, but by admission they all have the same type of 5-element Erfle design, including the 804ED, Kestrel, and Model 820.  To frame the issue, I started by presenting two 804 specimens that are each labeled "Multi-Coated Optics," but obviously are quite different.  Chad and John appear to have the same HR/5 model that I do, so the question on the table now is whether the HR/5 marked "Fully Multi-Coated" is the same or different.  If there is no red reflection in the FMC HR/5 it is different.  If there is a red reflection, we are left with the nasty "null-hypothesis" that there is no difference.  Strictly speaking, of course, it's nasty because it can't be proven.  I thought one way to finesse the problem might simply be to compare all the prism coatings from the objective side.  By all accounts, FMC binoculars should display green multi-coatings, whereas the MC specimens might or might not.  Well, sad news.  Save for the 804R, which may be uncoated, all of the other specimens display single-layer prism coatings independent of their MC or FMC markings.  This includes the 804ED, 10x50 Kestrel, and Model #820, — all marked FMC.  If someone can please produce a Swift FMC Porro that has more than a single-layer MgF prism coating please join in the conversation.  I would like to be wrong.  So, how come Nikon sticks with the rules and Swift does not?  As an example, here are the reflections from my new 8x32SE (s/n 550xxx).  See, the nice green (whoops, gold and blue) reflections from the front and back of the doublet, and strong green (oh, no, purple) reflection from the prism face?Maybe it's my eyes.  :-C</blockquote>

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