Archived posting to the Leica Users Group, 2009/11/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]hmm, well there is some correction going on in firmware even for DNG of course; the vignetting correction for example. I had thought Leica had already stated that they are dealing with moire in firmware. 2009/11/20 Dante Stella <dstella1 at ameritech.net> > Kodak is a little bit cagey with the info on the offset lenses on the > KAF-10500 and its bigger brother. I think the microlenses are tailored to > the application. > > What got me thinking about this is that I have an M8 and a Kodak 14n. > Neither has an AA filter, but the 14n also lacks microlenses. If you > process RAW files for both through Lightroom (so you don't get > contamination > from any in-camera correction), the 14n will produce insoluble moire much > more of the time - sometimes to the point where inducing diffraction by > stopping down the lens to f/11 is the solution. On the other hand, the > Leica virtually never hits this point. But given the tighter pixel pitch > and even higher-resolution lenses, one would expect it to. > > My hypothesis (which might be wrong) is that the little lenses (completely > offset or not) are acting as something of an AA filter - and what we all > take to be sharper pictures from no AA filter is really higher-contrast > pictures from higher-contrast lenses. Both the M8's and M9's resolutions > are 73lp/mm (at least according to Reichmann), and it should be routine to > cross that at wide apertures with M lenses. But the incidence of moire at > any aperture is so low as to suggest that the barrier rarely gets crossed. > That suggests something acting as a limiting factor on resolution. > > Something interesting, BTW, is the difference with and without AA filters. > If it is a relatively weak filter, as on the Nikon D3, removing the AA > filter actually does very little. Go here: > > http://bythom.com/nikond3xreview.htm > > And take a look at the with/without pairs for the D3 and D3x. Very > interesting. > > Dante > > > > On Nov 19, 2009, at 11:44 PM, Geoff Hopkinson wrote: > > > My assumption also. Perhaps there is info on this available from Kodak, > or > > Dante has it already? Interesting technically anyway. > > > > 2009/11/20 Tim Gray <tgray at 125px.com> > > > >> On Thu 19, Nov'09 at 10:37 PM -0500, Dante Stella wrote: > >> > >>> They do span more than one pixel - that's why they're called offset. > And > >>> that is why I asked. > >>> > >> > >> Ahh, I wasn't aware that they did that. I interpreted the offset > >> microlenses as not being centered directly over a pixel, but still > funneling > >> in light into just one pixel. Thus, enabling light to come in at more > >> oblique angles and still be captured. I drew an ascii diagram, but I'm > sure > >> most everyone's mail client will mangle it, unless you have monospaced > >> fonts. > >> > >> ------- > >> \ | > >> \ | <- offset lens > >> \___| > >> | | <- pixel > >> ---- > >> As opposed to > >> > >> ------- > >> \ / <- non-offset lens > >> \___/ > >> | | <- pixel > >> ---- > >> > >> > >> _______________________________________________ > >> Leica Users Group. > >> See http://leica-users.org/mailman/listinfo/lug for more information > >> > > > > > > > > -- > > Cheers > > Geoff > > http://www.pbase.com/hoppyman > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > -- Cheers Geoff http://www.pbase.com/hoppyman