Steve C
Well-known member
I suppose I use what might be considered a variation of the pebble test. This is the talus slope test. Some of the rocks are bigger than a car. The slopes abound around here and I can get them from 1.5 to 4.5 miles away. I can get closer, but the Klamath Hills are from 1-2 miles straight south and can be viewed from a tripod on the back porch. Stukel Mountain is further away to the east and is less handy because I have to move everything.
I use this as a simple, basic test. I am not looking for arc seconds or arc rocks, just a comparative view. The question is a basic one. If circumstances demanded an accurate count of rocks in the fov, could I do it from the image I'm looking at or not. The pebble test it seems is likely very much the same thing, just smaller rocks and closer distances. Can the same rock or pebble be viewed with the same or less apparent sharpness at the same distance, or not.
At any rate, it works pretty well. Image differences can be sorted out pretty quickly. All three Maven binoculars do very well here, at least as well as the Swarovski's I have or have had, as one example.
If I feel the need for more technical accuracy, I break out a resolution chart. However I have some doubts about those as well. For example, I once was at the Kruger Optics facility not far from my home exchanging a faulty Caldera binocular. The engineer was a friendly fellow and offered to let me participate in some tests to see what was done and how they did it. The resolution test was illuminating. He set up a binocular (the one I have now because of the superior resolution and collimation precision) and pronounced it to have x arc seconds resolution. He said it was because the bars in a particular section of the USAF chart were visible. I looked and thought if I was doing the test, I would have used the next size larger set of bars.
I use this as a simple, basic test. I am not looking for arc seconds or arc rocks, just a comparative view. The question is a basic one. If circumstances demanded an accurate count of rocks in the fov, could I do it from the image I'm looking at or not. The pebble test it seems is likely very much the same thing, just smaller rocks and closer distances. Can the same rock or pebble be viewed with the same or less apparent sharpness at the same distance, or not.
At any rate, it works pretty well. Image differences can be sorted out pretty quickly. All three Maven binoculars do very well here, at least as well as the Swarovski's I have or have had, as one example.
If I feel the need for more technical accuracy, I break out a resolution chart. However I have some doubts about those as well. For example, I once was at the Kruger Optics facility not far from my home exchanging a faulty Caldera binocular. The engineer was a friendly fellow and offered to let me participate in some tests to see what was done and how they did it. The resolution test was illuminating. He set up a binocular (the one I have now because of the superior resolution and collimation precision) and pronounced it to have x arc seconds resolution. He said it was because the bars in a particular section of the USAF chart were visible. I looked and thought if I was doing the test, I would have used the next size larger set of bars.
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