Re: A Lens?

----- Original Message -----
From: "Richard M. Koolish" <koolish@bbn.com>

> > Guillermo writes
>
> > BTW, taking about ZP, there is an article in that Shutterbug Feb/2001
> > edition about some Canon glass lenses using Diffractive Optics, the same
> > principle ZP lenses use. This new lenses (no yet released) use fresnel
> > lenses in combination with glass lenses.

> I thought the Shutterbug article completely confused diffraction
> and refraction, since a fresnel lens works by ordinary lens refraction
> and not by diffraction. The Canon lens could have a diffractive
> element of some kind and it would be interesting to see the Canon
> explanation rather than the garbled Shutterbug article.

You are right fresnels use refraction as glass lenses do. This Canon
technology uses diffraction grating elements, this site has a better article
that the Shutterbug's one:

http://www.dpreview.com/news/0009/00090604canon_400do.asp

Guillermo
Received on Thu Jan 18 14:09:29 2001