Adhoc,
There are two specification stadards covered by ISO14133. These were revised last year and are the instrument resolution standard was actually relaxed for some models
The Synpix Knight D-ED x32 8.0" specification falls outside the higher 14122-2 standard but the x42 (5.5") and x50 (5.0") comply. Of course these are maximum values and individual sample may be better. They generally need to be quite a bit better to impress me. The best binoculars could be around 4.5", 3.5" and 2.5" or better for 8x32, x42 and x50 respectively, but I don't find that a reliable indicator of sharpness. As you know I find a stopped down resolution value very much more useful.
20/20 or 120 arcsecond acuity. Magnified 8 times, that gives a visulal limit on detail of 120/8= 15 arcseconds. Providing the stopped down resolution of the binocular is better than 15" it's the eyesight that will be limiting not the binocular. That $25 binocular had a stopped down value of 14.5". My best result for an 8x is 5.8" or 2.5x better.
Measured light levels, random distances, using USAF 1951, Snellen, Landolt C and tumbling E charts.
David
There are two specification stadards covered by ISO14133. These were revised last year and are the instrument resolution standard was actually relaxed for some models
The Synpix Knight D-ED x32 8.0" specification falls outside the higher 14122-2 standard but the x42 (5.5") and x50 (5.0") comply. Of course these are maximum values and individual sample may be better. They generally need to be quite a bit better to impress me. The best binoculars could be around 4.5", 3.5" and 2.5" or better for 8x32, x42 and x50 respectively, but I don't find that a reliable indicator of sharpness. As you know I find a stopped down resolution value very much more useful.
20/20 or 120 arcsecond acuity. Magnified 8 times, that gives a visulal limit on detail of 120/8= 15 arcseconds. Providing the stopped down resolution of the binocular is better than 15" it's the eyesight that will be limiting not the binocular. That $25 binocular had a stopped down value of 14.5". My best result for an 8x is 5.8" or 2.5x better.
Measured light levels, random distances, using USAF 1951, Snellen, Landolt C and tumbling E charts.
David
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