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Message: <blockquote data-quote="kabsetz" data-source="post: 3307803" data-attributes="member: 10167">Chosun, Ed,On the efficiency graph, I also thought that the reason the tripod-mounted efficiencies were that far from theoretical efficiencies was because of what binoculars mostly were like in the 1980s. A good modern binocular, especially a sample close to diffraction limited in its optics and in situations where possible stray light issues do not mess things up too much is what I had in mind when speaking about 95% or better. The SLC HD 8x42 is a good example of what I mean.On IS and Canon in particular, I'm actually not in disagreement with Chosun. The 15x50 is stretching the abilities of the IS system, and I'm yet to see a sample that did not show at least some visible artifacts. There is also probably quite a wide range of sample variation. That said, unless the sample is really quite bad, you will be able to see much smaller detail with IS on than with it off.The 10x42 words much better, for two reasons. Firstly, with much lower magnification, the residual image movement on the retina is much reduced, and secondly, since the optics are better the artifacts can do more of their thing before the compound aberrations become visible. But there are sample differences among these as well, and they can also suffer from weak batteries.Kimmo</blockquote>