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Calculating the distance between the optical center and focal length

  1. Mar 27, 2015 #1
    -Hello everyone. At school, I studied about convex lense and concave lense. They are very interesting, we learned about how lights would be after going through the lense. But what I want to ask is how we can calculate the distance between optical center and focal (I means focal length). Focal length is a constant, but is there any formular which can give us the value of focal length .

    I would be grateful it someone could help :)
  2. jcsd
  3. Mar 27, 2015 #2


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    Staff Emeritus
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    Per wiki:http://en.wikipedia.org/wiki/Focal_length#Thin_lens_approximation

    Real lenses aren't thin lenses, but this is a good approximation to use in many cases.
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