Archived posting to the Leica Users Group, 2009/01/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Don, thanks for your input there. I don't recall that discussion on the sensor in detail. I have found the test site referred to by Dante which is very interesting. I did locate the LFI discussion regarding the non-linear way the sensor information is compressed into its 8 bit form before later reconstruction. I won't pursue this longer on the list. Of course in all of this I was explaining a method that I prefer rather than expecting to convert anyone else. The majority of folks look to be comfortable with the negative exposure adjustment method. The whole area is a complex one and we each place different weight on different attributes, I think. Noise in shadows being exacerbated by under-exposure is a big issue for me. Sometimes too simple assumptions regarding terminology differ too. For example 'over-exposure' Methods as well. I use Auto exposure but try to meter carefully and then lock that reading and recompose (where practical and warranted). 2009/1/20 Don Dory <don.dory@gmail.com> > Geoff, > If you recall from the discussions of the Kodak sensor when the M8 was > originally announced one of the technical items that stood out was that the > bias was toward the low end of dynamic range. Most sensors show a bias one > way or the other and the Kodak sensor in the M8 does a better job > distinguishing small differences in light values in the dark areas than in > the light. Which is why most of us have dialed in a negative exposure > compensation to avoid blowing the highlights. > > On Tue, Jan 20, 2009 at 1:34 AM, Geoff Hopkinson <hopsternew@gmail.com > >wrote: > > > Dante can you point me to some good data/analysis/examples that have > > brought > > you to these conclusions? I'm very keen to get the best from my M8 and > > these > > statements don't fit with my understanding at all. > > > > 2009/1/20 Dante Stella <dstella1@ameritech.net> > > > > > > > > The DxOMark site is interesting, primarily the DR comparisons. Run a > > > comparison on the M8 against any modern DSLR (Nikon or Canon) and > puzzle > > > about the arguments/assertions that the dynamic range of a Leica is > > > "better." A better word would be "average." Compared to cameras > > equipped > > > with Kodak's 24x36 sensors, Fuji's Super CCDs, and Nikon's post-D2x > > sensors, > > > it's actually a bit behind the curve. I'm sure that despite objective > > > comparisons like DxO's, we're still going to hear claims that the M8 is > > > notable for its "dynamic range" (c.f. here, the Leica Camera forum, and > > > RangefinderForum.com). Or does someone want to poke holes in DxO's > > > methodology? > > > > > > After two years of working on M8 DNG files, I can say that the DR and > > > distribution of information in DNG files are my biggest issues with the > > M8. > > > It's not the spatial resolution or the sensor size. It's not even the > > > rickety 50-year old rangefinder, a different effective back focus, or > an > > > annoying bottom-plate load. > > > > > > Many of us like shooting pictures that have tonality in the highlights. > > On > > > film, we'd use TMY, shoot normally, and err on the short side of > > > development. No problem. But on an M8, we have to underexpose. This > > > pushes the moderately low tones down into the noisier nether regions - > > and > > > some of the time, we end up needlessly sacrificing the camera's DR in > the > > > process just so we can be sure we don't blow it on the high end of the > > > scale. > > > > > > On the next Leica digital, we need more bits, and we need them in the > > > highlights. That way, we can shoot for the shadows and simply reign in > > any > > > unruly highlights. And by reign in, I mean with both color and > tonality. > > > When you recover highlights on an M8 as currently configured, you get > > color > > > (if you're lucky), but the tonality is flat - like film that shouldered > > off. > > > Not good for things like clouds and snow-capped mountains. Or human > > faces > > > with hot spots. > > > > > > I'm still puzzled about why Leica decided to so much information to > > > shadows. Pictures taken in bright light generally don't have a lot of > > > shadow interest. Low-light situations are either "all shadows," in > which > > > case they can be shot normally (since they have very constrained > dynamic > > > ranges) - or they are mostly shadows with bright highlights - in which > > case > > > you need more highlight recovery. So what was the imagined situation > > that > > > prompted the composition of Leica DNG files? > > > > > > Dante > > > > > > ____________ > > > Dante Stella > > > http://www.dantestella.com > > > > > > > > > _______________________________________________ > > > Leica Users Group. > > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > > > > > > > > -- > > Cheers > > Geoff > > Life's too short for slow zooms > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > > > -- > Don > don.dory@gmail.com > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > -- Cheers Geoff Life's too short for slow zooms