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Message: <blockquote data-quote="typo" data-source="post: 3148104" data-attributes="member: 83808">Binastro,I seem to remember we did a rough calculation on that pimple on the chimney pot a while back and came up with something like 15 arcseconds. 8x magnification would make that 120 arcseconds. If I understand what you said correctly then the IS makes a difference to how distinct the pimple is. I know an ink dot on white paper is not the same thing, but I made a range of spots of different sizes with a very fine marker pen and viewed them hand held and braced with my 8x.The 0.9mm spot (16.9" x 8 = 135") was very clear hand held. The 0.5 spot (9.4" x 8 = 75") was clearly visible most of the time, disappearing briefly every heart beat hand held, but was quite distinct when braced. The 0.4mm spot (7.5" x 8 = 60") had less ink and more a mid grey rather than black and was only visible 10-20% of the time hand held and probably still under 50% of the time when braced. The bracing appeared to have eliminated the major oscillations not the micro ones. It's worth mentioning that the surface brightness was 1500 cd/m2 at midday and way too high for my best results but I thought you might be interested all the same.It's 18 months since I last tried the Canon IS range so I'm struggling to recall what if any benefit I noted at the time. My best recollection was that some models, but I don't remember which, appeared to dampen the heart beat oscillations but seemingly not the micro ones so might have improved the 0.5mm results which should be obvious, but maybe not the others. All wild guessing of course. On certain days we get the Luton flight path routed a mile or two from us, but I don't know the exact distance. Hand held the EasyJet lettering on the tail was very readable, but maybe a little fuzzy. It was sharper braced.I don't know if this helps any?DavidI found a map of the flight path, and given the angle of view, I was observing the plane at a range of 2.5 to 3km or 1.55-1.86 miles.</blockquote>

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