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    I have a two lens problem. I have been given the focal lengths of two lenses and their separation. using matrix methods, I have calculated their combined focal length. the question now asks for the magnification. How do I calculate this?

    I know that M(total) = M1 * M2 but I am unsure on how to calculate the individual magnifications. Possibly using M=-v/u but what is v and u?
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      Are these two lenses meant to be configured as a telescope or microscope? If so, the image distance is usually either set to infinity (telescope in normal adjustment) or 25cm - the so called near point.
      The magnification clearly depends on the object and image positions.
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      well it doesnt say anything about the object distance which confused me. altho i have heard of the visual near point, altho its unmentioned in the problem
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        (Original post by samueltaylor123)
        well it doesnt say anything about the object distance which confused me. altho i have heard of the visual near point, altho its unmentioned in the problem
        What does it say? It would help if you gave more information.
        Is it 2 thin lenses separated by a distance less than the focal length of the 1st lens?
        Are they separated by a distance greater than the sum of their focal lengths.
        What type of lens are they? Both convex?
        Without this information I can only repeat my 1st suggestion, that you assume the image to be at either infinity or 25cm.
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        A huygens eyepiece consists of 2 thin lenses at focal lengths 20mm and 30mm separated by 25mm. calculate the focal length of the eyepiece (which i have done) and hence it's magnification.
       
       
       
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