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Message: <blockquote data-quote="Binastro" data-source="post: 3143358" data-attributes="member: 111403">. If I were to do tests of binoculars both tripod mounted and handheld I would not use test charts as these consist of known detail.Usually, when discoveries are made, they are of unknown detail.So I would try to get as close to perceiving unknown detail as possible.I thought that maybe one should construct 100 words consisting of five letters but with no meaning and use these at different distances to find out at what distance they could be accurately made out either with a tripod mounted binocular or a handheld binocular.There may in fact be such systems that opticians use but I'm not aware of them.Many years ago I was with my cousin in the Street and I said I had quite good eyes, and I asked him how far he could read the number plates on cars that were parked on the side of the road. I read them out as far as I could and I was totally amazed that he could read number plates up to almost exactly twice the distance I could.My eyesight was 20/15 and I didn't wear glasses. Now I still manage 20/15 or 24/16 but I need correction glasses.My cousin's vision was about 20/7.5 or in metres about 6/2.2.So what I would do testing the binoculars is to find a very large car park such as at Bluewater or alternatively a long road with cars parked all the way along it.I can see numberplates up to about 50 m although I cannot quite remember the exact figure. So my cousin could just read number plates up to about 100 m.For a tripod mounted very good 10 times binocular one might need a road 1000 m long with cars parked along its whole length.One would need an independent third party with a good spotting scope, say 20x to 60×80 mm to check the correctness or otherwise of the person using the binoculars.It might be for instance that the observer could see numberplates up to 700 m tripod mounted and 400 m handheld.Slight correction might be needed as the angle at 700 m might be 15° and at 400 m 25°.Ideally, the observer should be at right angles to the number plate.One would need one or preferably two high quality laser rangefinders either binoculars or monoculars to check the distance to the  number plates seen.I know that tests of number plates do not equate to tests using test charts, but at least one is checking unknown detail as opposed to known detail.It is not quite unknown detail as one can guess some of the numbers or letters on a number plate.</blockquote>

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