Archived posting to the Leica Users Group, 2009/11/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]"Some" processing being the operative word... I will probably put the question on microlenses directly to Kodak - which is usually a lot more forthcoming with technical information than Leica typically is. Dante On Nov 20, 2009, at 1:45 AM, Geoff Hopkinson wrote: > 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 > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information