I am not sure how else to explain it.   I expect that a spherical lens has
a lower effective area than a much flatter convex glass lens or a fresnel
lens.  I am looking for how to determine what the effective diameter is.


I may be wrong on this, that's why I asked.


On Wed, Aug 24, 2016 at 10:58 AM, Brooke Clarke <brooke@pacific.net> wrote:

> Hi David:
>
> It would help if you told us what you're trying to do.
> For example here's a 4" diameter spherical glass lens used to burn paper,
> called a Campbell Stokes Sunshine Recorder:
> http://www.prc68.com/I/CampbellStokes.html
>
> Here small glass balls are used to make a simple (not compound) microscop=
e:
> http://www.prc68.com/I/SimpleMicroscopes.html
> The above link contains technical details for ball, half ball and bullet
> lenses as well as a replica Leeuwenhoek
> microscope.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> The lesser of evils is still evil.
>
>
>
> --
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> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
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