Archived posting to the Leica Users Group, 2004/11/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> I don't know our > uncalibrated eyeballs can do as well as they do. I had an interesting discussion with a cabinet maker and later with an Intensive Care physician several years ago about the ability of our "uncalibrated eyeballs" to discern "out-of-true" lines. Cabinet makers, I learned, have always known that the unaided human eye (assuming average eyesight), can detect 1/64" and 1/128" over a length of 3'. The physician was treating my wife, who had a Swan-Ganz (sp?) catheter. For the treatment to work properly, as I recall, a long level had to extended horizontally from the catheter entry site in her chest out to the side of the patient. Several nurses were fussing with the thing when the doc came in and, rather impatiently explained to the nurses that the human eye was more capable of detecting out-of-level conditions than by using the level. He then proceeded to demonstrate, and he was right! Amazing what the eye can do! Ken Frazier