Actually the only specific claim I've seen from Sigma is: "Super Multi Layer (SML) coating reduces the ghost caused by reflections from the surface of digital image sensors."
Assuming Pentax was wise enough to put an anti reflective coating on the filter in front of the CCD, this wasn't much of a challenge. ;-) In the case of the 50/2.8 Macro at least, the size and weight haven't changed at all. The letters DG and the price tag may be about the only difference. I went with a like new used EX for 1/2 the price of an EX DG. Been very pleased with it on the D. Don > -----Original Message----- > From: Mark Roberts [mailto:[EMAIL PROTECTED] > Sent: Saturday, April 09, 2005 6:33 AM > To: [email protected] > Subject: Re: DG lenses > > > "John Whittingham" <[EMAIL PROTECTED]> wrote: > > >> They will. Sigma's "DG" lenses are full-frame but "optimized for > >> digital" (I'm as suspicious of this digital optimization as > herb Keppler > >> is.) Their digital-only (small image circle) lenses are > designated "DC". > > > >Thanks Mark, the 70-200 is still definitely an option then. I'm > not familiar > >with Keppler's opinion on digital optimization, would you care > to elaborate > >or post a link to the article? > > He's asked for examples of both "old versions" and "digitally optimized > version" of the same lens, along with suggestions as to what kind of > photo situations will best reveal the improvements of the "optimization" > so that he can compare the differences. So far no manufacturer has taken > him up on it. He has drawn a somewhat cynical (but probably accurate) > conclusion from this ;-) > > -- > Mark Roberts > Photography and writing > www.robertstech.com >
