http://blog.roodo.com/citta/archives/cat_679507.html A photograph is a secret about a secret. The more it tells you the less you know. _uacct = "UA-1001360-1"; urchinTracker(); zh-tw Roodo Blog System All Rights Reserved

Before:


"A concave lens of flint glass is commonly combined with a convex lens of crown glass to produce an achromatic doublet"

by John Dollond

Crown glass: low refractive index (≒1.52), low dispersion (with Abbe numbers around 60)
Flint glass: high refractive index (1.45-2.00), low dispersion (with Abbe numbers around 50-55)

More details:CLN, No.12/2000

]]> http://blog.roodo.com/citta/archives/9357551.html http://blog.roodo.com/citta/archives/9357551.html Optics．光學筆記 Thu, 02 Jul 2009 05:32:10 +0800