Message text written by INTERNET:[EMAIL PROTECTED] >If I'm reading this right, somebody[s] think you can tell an aspheric lens from a NON-aspheric lens by some sort of measurement WE can make? If I read right, disabuse yourselves of that idea. Most aspheric optics are aspheric (vary from being perfectly spherical) by something in the order of several wavelengths of light! Nothing we can measure with _our_ crude instruments. <
if they designed the lens differently, that is what they are looking for, not the actual lens itself. however, take a look at the Sigma 15-30 zoom. the front element is distinctly nonspherical, almost conical. there are other lenses where the difference is easily visible too. Herb....
