Oh yeah! (where's the *slap forehead* smiley) I forgot about binning!
Nice one Fred...
I read about the 2.5 figure from a website I found surfing through topics on IIS. It's a bit old - but was here:
http://www.sctscopes.net/Photo_Basic...cd_camera.html
Might be worthwhile asking if that's actually a realistic aim, given advances in technology and quality.