wlaidlaw Posted February 28, 2007 Share #1 Â Posted February 28, 2007 Advertisement (gone after registration) I was out taking some pictures this morning in the brief intervals between rain and on starting to process the images from DNG in Photoshop, I noticed quite heavy colour fringing. I was using the Biogon 21mm on the M8. Example below. Has anyone else had this problem with the B21. Â Wilson Link to post Share on other sites More sharing options...
jaapv Posted February 28, 2007 Share #2 Â Posted February 28, 2007 Not at all. I'll try to dig out some shots tonight time permitting. Link to post Share on other sites More sharing options...
pascal_meheut Posted February 28, 2007 Share #3 Â Posted February 28, 2007 Photoshop adds some CA. Here is a comparison with C1 on the left. The lens was the 28mm/2 ASPH. Link to post Share on other sites More sharing options...
jaapv Posted February 28, 2007 Share #4 Â Posted February 28, 2007 That might be the difference, I convert using C1 Link to post Share on other sites More sharing options...
wlaidlaw Posted February 28, 2007 Author Share #5 Â Posted February 28, 2007 That might be the difference, I convert using C1 Â Here is the same image processed with C1 - not terribly well as just learning C1 but you can see that the colour fringing is definitely less. However, detail preservation is considerably inferior to PSE4. Â Wilson Link to post Share on other sites More sharing options...
jaapv Posted February 28, 2007 Share #6 Â Posted February 28, 2007 This part looks pretty overexposed. Maybe you should check the exposure settings Link to post Share on other sites More sharing options...
jaapv Posted February 28, 2007 Share #7 Â Posted February 28, 2007 Advertisement (gone after registration) Oh yes, oh yes. You are so right.... (firmware 1.06) Â Â Link to post Share on other sites More sharing options...
wlaidlaw Posted February 28, 2007 Author Share #8 Â Posted February 28, 2007 Jaap, Â If I do not have to build an ark tomorrow and start collecting the animals two by two, I will go and try the same photos with 1.091. I will also try with the Biogon 35 to see if it is CA from the lens or maybe CA in the sensor microlenses, dependant upon light angle of incidence. I will process with PS, C1 and Lightzone, to see if there is any difference. The original DNG was a little dark and I think I pulled the exposure up in the C1 process a bit too much, which may have resulted in the loss of detail. Â Wilson Link to post Share on other sites More sharing options...
woodyspedden Posted March 1, 2007 Share #9  Posted March 1, 2007 Jaap, If I do not have to build an ark tomorrow and start collecting the animals two by two, I will go and try the same photos with 1.091. I will also try with the Biogon 35 to see if it is CA from the lens or maybe CA in the sensor microlenses, dependant upon light angle of incidence. I will process with PS, C1 and Lightzone, to see if there is any difference. The original DNG was a little dark and I think I pulled the exposure up in the C1 process a bit too much, which may have resulted in the loss of detail.  Wilson  Wilson  you have to be really careful to note the difference between CA (a lens problem) and purple fringing (a sensor problem due to overexposure due to super high contrast images). They may at first be perceived to be the same problem but are due to totally different physical phenomena.  Woody Link to post Share on other sites More sharing options...
35mmSummicron Posted March 1, 2007 Share #10 Â Posted March 1, 2007 just wanted to say that while it is annoying to see/deal with BOTH CA and sensor blooming are unfortunate realities of shooting digital, and not exclusive to Leica M8's. Â Canon's, Nikons, and even high end digital backs have this. Leica glass is supposed to be very well corrected (read, well corrected, but not necessarily 100% free from abberations), but keep in mind the newest optical forumlas are also of very high contrast, so bare branches against a white sky, you are bound to get some colour effects. i have noticed the same with zeiss glass as well. Â from my understanding, much like how you can adjust/control CA in ACR, the H3D has incamera and software controls to help reduce the effects. it seems aside from more megapixels, more elaborate software to correct for lens imperfections is how digital photography is evolving and improving. it will be interesting to see how C1 version 4 handles this when it comes out (and in turn how it handles M8 DNG's). Â Â i personally control this in photoshop and locally get rid of it with the desaturate-sponge tool. **it helps if you use a drawing tablet** Â /a Link to post Share on other sites More sharing options...
pascal_meheut Posted March 1, 2007 Share #11 Â Posted March 1, 2007 Details preservation should be quite good in C1 once you know how to use it. Be careful to uncheck the "noise removal" optio but not the "color noise". Link to post Share on other sites More sharing options...
wlaidlaw Posted March 1, 2007 Author Share #12 Â Posted March 1, 2007 I think the point I was trying to make was that the Biogon 21 seemed to accentuate this phenomenon more that the Biogon 35. My personal feeling was that this was a sensor characteristic but could possibly be dependant on light angle incidence and thus the exit pupil to sensor distance. The Biogon design has traditionally had a short exit pupil to imaging medium distance (for an extreme example look at the Biogon G21 for the G1/2 cameras). I know that it is possible to reduce this phenomenon by various post-production techniques but I was surprised by the extent of it on the "as taken" DNG/RAW and was wondering if others with the B21 had noticed it. It would appear that the answer is yes, so I now am reasonably confident that it is not a lens fault but a camera/lens characteristic, which I will have to live with and work round - more "scientific" tests today with 1.091. Â Wilson Link to post Share on other sites More sharing options...
stunsworth Posted March 1, 2007 Share #13 Â Posted March 1, 2007 CA is a lens phenominon isn't it? As Pascal hints at it sounds as if C1 is automatically attempting to correct it. You have to do this manually in ACR. Link to post Share on other sites More sharing options...
wlaidlaw Posted March 1, 2007 Author Share #14 Â Posted March 1, 2007 CA is a lens phenominon isn't it? As Pascal hints at it sounds as if C1 is automatically attempting to correct it. You have to do this manually in ACR. Â Steve, Â I would agree and I think the action of C1 resulted in a reduction of quality, while it was dealing with the colour finging. It is a case of TANSAAFL (There ain't no such thing as a free lunch). On balance, I think I would rather live with a bit of colour fringing using ACR than lose so much definition. I have not tried this image with Lightzone, which might be a happy medium. The preview screen on Lightzone is a bit small even on my 22" monitors and unlike PS, you can't pull all the tool boxes into a different screen and expand the preview screen. Â Wilson Link to post Share on other sites More sharing options...
pascal_meheut Posted March 1, 2007 Share #15 Â Posted March 1, 2007 I do not think this is only CA. It may have something to do with the way the programs handle bayer matrix in high-constrast zones. Anyway and once again, C1 gives as much details as ACR, at least... If you look at the comparison I posted, it even has more. Link to post Share on other sites More sharing options...
jaapv Posted March 1, 2007 Share #16 Â Posted March 1, 2007 My shot was converted in C1LE at default settings. Link to post Share on other sites More sharing options...
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