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Message: <blockquote data-quote="jcbouget" data-source="post: 1346782" data-attributes="member: 17837">I’ve not read all this thread, which contains a lot of interesting reflections, but I would like to make two remarks to answer the question above :1. I have the Nikon SE 12x50, the Fujinon 16x70 FMT SX2, and other first class binoculars. I don’t consider that Porro prism binoculars are always optically superior to Roof prism binoculars. In fact, they may be better in some areas, and worse in others.About sharpness, although the Nikon is excellent, it is surpassed by my old Zeiss Classic 10x40 BGA T*P, a roof prism model, which is one of the sharpest binoculars of my small collection. The Fujinon 16x70 offers a good sharpness, but is clearly not among the best ones.The color rendition of the Nikon shows a significant pink bias, whereas my Zeiss 10x42 FL and other binoculars have a much more neutral yellow/green bias.The contrast of the Nikon SE is slightly better than the Zeiss FL, but the difference is very hard to see. The Nikon and the Fujinon have a very good edge sharpness compared to the Zeiss FL, but it is probably due to their complex eyepiece design, not to the use of Porro prisms.2.  A very instructive experiment consists in examining the image of a bright point by increasing the magnification of the binocular thanks to an additional device (a booster, a finder, another binocular…). It is sad that very few binocular enthusiasts make this test.The test reveals that binoculars are affected by large amounts of coma, astigmatism, or spherical aberration, even the most expensive ones. Furthermore, I’ve not seen a binocular whose sharpness could not be roughly explained by the quality of the diffraction pattern. For example, my Nikon SE has some astigmatism and some coma in both barrels, whereas my Zeiss 10x40 Classic has no astigmatism and no coma.My opinion is that sharpness is essentially determined by the quality of the alignment of the optical components inside the binocular. The variations of optical aberrations produced by the low tolerances of binoculars are too wide to attribute the sharpness differences to other sources, for example alterations due to phase coatings.I believe that roof prisms binoculars, which have complex objectives made of 3 or 4 lenses, internal focusing, and short focal ratio, are much more sensitive to misalignment that the simple doublet objectives used in Porro prism binoculars. That could explained why Porro prism binoculars can easily provide very sharp images, even in moderately expensive models. That could also explain the difficulties encountered by Swarovski in the manufacturing of the new EL : this model has not only a complex objective, but also a complex eyepiece design, and keeping all the lenses in a small package probably puts a severe constraint in manufacturing tolerances.Jean-Charles</blockquote>

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