Thank you so much for your quick answer. My problem is actually related with a correct determination of the focal curve of an achromatic doublet.
In my problem I am using a standard solution, which consists of a biconvex Crown glass lens attached to a plano-concave Flint Glass Lens.
In...
You can find the formulas here: http://pt.scribd.com/doc/58102523/138/Achromatic-Doublet-Lens-Design
but they can also be found for example in the classical book Principles of Optics of Max Born and Wolf..
You are right, but I forgot to mention that the lenses are thin lenses and that they are in contact with each other. In this case, the formulas I mentioned are the correct ones.
I have a problem with the determination of the correct focal curve of an achromatic double.
I'm considering here a doublet formed by a biconvex Flint Glass lens attached to a plano-concave crown glass lens. ( I know that the typical design of the doublet is a biconvex crown lens attach to a...