From: boyd@apt0.sao.arizona.edu   
      
   Laurie wrote:   
   >     Optical devices generally have their magnification specified as nX;   
   > e.g. 10X, meaning that the magnification produces an image that is ten   
   > times larger than the original.   
   >     Yet, when one looks through a "10X" binocular with one eye and   
   > without with the other eye, and then overlaps the two images, one sees   
   > about a 2-3 times larger image.   
   >     Why?   
   >     Laurie   
      
   Maybe the manufacturer thinks they should  specify the magnification in   
   terms of area or volume rather than linear dimension.   10x apparent   
   area would require  3.16X  increase in linear dimensions.   Likewise for   
   a 10x appearance in object volume of an object with the same proportions   
   the linear magnification should  only be  2.15X   
      
   What does an object which appears to be "10 times larger" mean to you?   
      
   Are those binoculars perhaps made in China?   I've seen cheap Chinese   
   fixed magnification riflescope with "mil-dot" reticles where the reticle   
   spacings aren't anywhere close to being 1 milliradian spacing.  I'm not   
   sure if it's matter of lying,  stupidity,  or they simply don't care as   
   long as it sells.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)