It's a variation of SMC, differently tuned for increasing light transmission at different wawelengths than SMC. It is used on some inner elements where reflections would lead to ghost images. You cannot use ghostless everywhere to replace smc, since you'd get a color cast on the lens, but when used where needed, it gives you further freedom from ghost images compared to using smc alone.
It was developed by Pentax to supply a detection system capable to read front car plates at night (hence with front lights straight into the camera). Pentax was the only manufacturer capable to succeed in such a hard task. Then, Ghostless coating was also used on camera lenses for some inner elements of star lenses in early nineties (I think the FA* 85/1,4 the FA* 28-70/2.8, FA* 80-200/2.8 and so on). I've been told that by a Pentax designer several years ago. Dario ----- Original Message ----- From: "Margus Männik" <[EMAIL PROTECTED]> To: "Pentax-Discuss Mail List" <pdml@pdml.net> Sent: Sunday, October 08, 2006 10:53 PM Subject: Re: D-Xenogon 35 > OK, can anyone explain more closely what is "Ghostless Coating"? Further > development of SMC or just a marketing hype? > > BR, Margus > > Steve Jolly wrote: > >>"SMC" was revolutionary 30-odd years ago, but these days anyone with the >>right software and a basic understanding of optics can design high >>performance multi-layer optical coatings. SMC is just a brand. >> > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
