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Message: <blockquote data-quote="Binastro" data-source="post: 3239746" data-attributes="member: 111403">. Thanks Piergiovanni,. Regarding previous posts here. It states that the eyepieces are five elements in four groups.However, the side view diagram seems to indicate five elements in three groups, including the doublet field flattener. The basic eyepiece shown here has only three elements it seems.As I recall, another diagram suggested that the eyepieces are four element plus the doublet field flattener, making six elements.Assuming that there are five elements including the doublet field flattener, it may be that originally there was only a single element field flattener +4 elements in the actual eyepiece.Whatever the true position is, it seems that different diagrams from Canon suggest different configurations.I think that 10×42 L may have a total of seven elements. I cannot remember how many elements the eyepieces of the 15×50 and 18×50 have.Whatever the position is I think that the higher end Canon image stabilised binoculars have better edge performance than the 10×30 and 12×36. Although, the original 12×36 Mark one had a wider field of view and better edge performance, but this was a heavy binocular in comparison with the later 12 x 36.It would seem to me that the current and recent 10×30 and 12×36 don't have optical windows, whereas all the others including the 8×25 seem to have optical windows.The nice Italian test does show benefits but maybe not overwhelmingly better, at least the basics of the binoculars remain the same.</blockquote>

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