Re: [Phys-l] lens combinations

[John Denker <jsd@av8n.com>]

On 05/25/2010 04:58 AM, Anthony Lapinski wrote:
> For my optics unit I am planning to do some lens combination problems in
> my honors classes. Our textbook (Cutnell & Johnson) has typical, standard
> problems. I am looking for more practical ones (involving actual devices)
> for my students to try. For example, a telephoto lens basically consists
> of a positive and negative lens combination. 

That basically describes a Barlow lens
  http://en.wikipedia.org/wiki/Barlow_lens

These things are commonly used in the amateur telescope community.
Ask around locally.  It should be easy to lay hands on examples.

It is straightforward to find the design equations:
  http://www.google.com/search?q=%22barlow+lens%22+equations
Example:
  http://www.astunit.com/tutorials/barlow.htm

=========================

If you want something very real and very important, but involving
deeper physics than the above, consider compound lenses, such as 
achromatic lenses
  http://en.wikipedia.org/wiki/Lens_%28optics%29#Compound_lenses
  http://en.wikipedia.org/wiki/Apochromat

To find the design equations:
  http://www.google.com/search?q=achromat+"v-number";
  http://www.google.com/search?q=achromat+"v-number"+site:.edu