Archived posting to the Leica Users Group, 2003/05/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Jim Congratulations! You did it again, without resorting to mysticism. I wondered why there were different requirements for digital vs. film lenses. Now what does a low pass cut-off filter look like? Jerry Jim Brick wrote: > At 02:51 PM 5/7/2003 -0500, George Lottermoser wrote: > > >For all techies who have found interest in the optical requirements of > >digital - Schneider has a white paper on their thoughts: > > > ><http://www.schneideroptics.com/info/white_papers/optics_for_digital_photography.pdf> > > > >Fond regards, > > > >G e o r g e L o t t e r m o s e r, imagist > > I've been pointing folks to that white paper for a couple of years now. And > I still get poo poo'ed. And I also said that this is why Schneider (and > others) make a complete set of LF lenses for digital. They are computed to > produce a lower MTF frequency than film lenses. This way a low pass cut-off > filter is not needed over the digital sensor. This increases sharpness in > many ways. > > All high-end digital SLR's that use film camera lenses have a low pass > cut-off filter over the sensor to dumb down the lens to match the sensor > pixel frequency. This is unnecessary with film because the grain structure > of film is random and much much tighter than current pixel spacing. > > For Kodak digital backs, you can buy this cut-off filter as an accessory, > specifically to quell aliasing. > > Jim > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html