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Message: <blockquote data-quote="Surveyor" data-source="post: 3174503" data-attributes="member: 50720">Hi ED,I use commercial software Ed, ISO specs. Starting prices around $100 to more than a non government entity can afford. There are numerous ones available plus a bunch of free ones. I have a MTF plug in for ImageJ and one called Java MTF, though I do not use them. You can Google those for a start to see if it is something you want to try.Since the coupling issue is a non factor to me I will avoid the discussion and just state that, to me, the coupling would be about the same as taking a picture trough a window.When I first started this, that was one of my concerns and I started out by measuring the lens and subtracting it from the bino figures in a spread sheet. There was so little difference that it did not justify the effort for comparative purposes. Even if the imaging lens had the same MTF as the bino, at 10x that would be about 10% of the bino apparent angular error. Then there is the fact that, like a booster for star testing or resolution, the exit pupil is only using a portion of the 40 mm imaging lens I use. BTW, I pretty much follow the ISO procedure but would not be able to state a repetitive error percentage since I have no known standards to compare against, but feel the comparison are valid as to the better unit.Also, see my comments to Kimmo about the correlation of resolution testing to the general MTF results.But even if there were substantial error it would be constant so the comparative value would still be valid. Look at how many tests are done using highly variable eyes as the detector for side by side comparisons and absolute determinations are made.No offense ever taken. I know that we just have different priorities. I am only interested in actual hardware differences and performance.Hello Kimmo,Unfortunately I am having problems with the computer I have my MTF stuff stored on. I thought it was a power supply fan but when I got it apart, found it to be the CPU fan so I am not running it more than I have to right now.There have been many over the one wave range, most of which went elsewhere quickly so I don’t really remember what they are. I have attached a plot from older software (though it compared well to the two later versions I have used) of one of the original Monarch 8x36. I bought two, one was out of collimation but had good resolution, so I sent it back for repair and it turned out to be a good budget bino. The other had a limiting resolution of about 7” (>250/Aperture) and I gave it to my neighbors boy to play with. The plot attached goes with it. Another memorable one was a Russian porro that was supposed to be 12x50 and measured 10x50 and also had subpar resolution. There was a Alpine 8x20, one vintage Zeiss that had been dropped and a bunch rebadged stuff that I had no idea who made.FWIW, I have not done any MTF in several years. I found that the limiting resolution was a very good predictor of what I would see and MTF did not add enough useful information to the general comparison to justify the setup time. Notable exceptions are when wanting to verify some theory or principal. One very memorable and useful period was when I took and 8x42 ELX and a good sample of the Zen-Ray 7x36 ED2 and ran a full series of resolution and MTF plots for many aperture and exit pupil stops. But then, adding one piece of useful information also brought about 10 more questions.So for general purposes I would think the limiting resolutions of 140-150/A would be like those above, <0.5 wave, 180-210/A will be somewhere in the .75 to 1.5 wave range and >250/A will generally plot with the drop hitting 10% contrast in the 10 to 20 c/d position and then snaking between the 0 and 10% contrast lines. Anything above about 1.5 waves is just too weak to make any sense of. Of course, I have seen some exceptions, but few.</blockquote>

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