On Sat, 20 Aug 2011 16:53:29 -0700 (PDT), Ron Cuaz
wrote:
How big in area of the an object say 5 meters away would appear to a

25 microns divided by 6.76 millimeters and then multiply by 5 meters.
The result will be some 18 millimeters.

And, yes, you must do some unit conversions while calculating this. I
suggest you convert all lengths to millimeters.