[Sca-cooks] Farsighted lenses

[Stefan li Rous]

Bear commented:
<<< Magnifying glasses are fairly simple to make (which is why reading glasses are cheap and OTC) reasonably accurate corrective lenses aren't. >>>

Yes. If the magnifying glass is x4 instead of x3, people just hold it differently. I'm not sure the medieval client, even if rich, could be super choosy.

But corrective glasses would need to be closer to spot on and distortions probably less easy to get around.

<<< I would think this would have been a 
trial and error process with a lot of rules of thumb, but it's worth noting 
Newton describes the optical properties of lenses in the 17th Century. >>>

Has this changed? Other than the price of having a bunch of lenses on hand?

Whenever I go into my optometrist there still seems to be a bunch of "Is this one better than the last?", "What about this one?", "Is this one better?", "Is this one better or worse?" etc. etc.

Of course once a particular lens is selected, today that lens can be reproduced with a reasonably high chance of success. And I can have it made out of glass, polycarbonate or other materials and coated with various coatings.

Stefan

--------
THLord Stefan li Rous    Barony of Bryn Gwlad    Kingdom of Ansteorra
   Mark S. Harris           Austin, Texas          StefanliRous at gmail.com
http://www.linkedin.com/in/marksharris
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