malsop Posted October 10, 2013 Share #1 Posted October 10, 2013 Advertisement (gone after registration) I have one image from my summer trip this year with a very unusual optical illusion or bad conversion from raw. The following image was shot with my Leica M (Typ 240) and the Summilux-M 35mm lens, handheld, f/11, 1/800, ISO 800. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! The image was shot raw, processed in Bridge/ACR CS6 and viewed in PS CS6 with the latest updates to Lightroom and PS, including ACR. Viewing the left mirror on the black Harley (my ride) at 100% (left below) and 300% (right below) it looks like there was a problem translating the chrome rim from raw. The rim of the mirror appears to be enlarged on the top relative to the bottom at the points where the discontinuity occurs on each side. I see no evidence of any aberration in the background or in the mirror image, just in the chrome rim. From this image …the chrome rim looks correct on the right-hand mirror of the black Harley. The left-hand mirror on the red Harley from this image shows a little bit of the same problem at the left-upper corner but not anywhere else. The right-hand mirror on the red Harley looks fine. If this is an optical illusion it sure takes the cake. I've not done a test to see if this can be reproduced with the same and different lenses under similar lighting since I'm in the middle of moving my base of operations to Texas. Anyone ever noticed something like this before? …with the Leica M? ...with other cameras? Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! The image was shot raw, processed in Bridge/ACR CS6 and viewed in PS CS6 with the latest updates to Lightroom and PS, including ACR. Viewing the left mirror on the black Harley (my ride) at 100% (left below) and 300% (right below) it looks like there was a problem translating the chrome rim from raw. The rim of the mirror appears to be enlarged on the top relative to the bottom at the points where the discontinuity occurs on each side. I see no evidence of any aberration in the background or in the mirror image, just in the chrome rim. From this image …the chrome rim looks correct on the right-hand mirror of the black Harley. The left-hand mirror on the red Harley from this image shows a little bit of the same problem at the left-upper corner but not anywhere else. The right-hand mirror on the red Harley looks fine. If this is an optical illusion it sure takes the cake. I've not done a test to see if this can be reproduced with the same and different lenses under similar lighting since I'm in the middle of moving my base of operations to Texas. Anyone ever noticed something like this before? …with the Leica M? ...with other cameras? ' data-webShareUrl='https://www.l-camera-forum.com/topic/214408-bad-conversion-from-raw/?do=findComment&comment=2438551'>More sharing options...
Advertisement Posted October 10, 2013 Posted October 10, 2013 Hi malsop, Take a look here Bad Conversion from RAW?. I'm sure you'll find what you were looking for!
lct Posted October 10, 2013 Share #2 Posted October 10, 2013 Never seen this so far but there seems to be a curious reflexion on the brick wall above the mirror as well. Would be interesting to process your file again with the same or preferably another raw converter. Link to post Share on other sites More sharing options...
250swb Posted October 10, 2013 Share #3 Posted October 10, 2013 The mirrors look superficially similar but are very subtly different in shape, are you sure you aren't inventing a conspiracy theory over what are just odd part numbers? Steve Link to post Share on other sites More sharing options...
malsop Posted October 10, 2013 Author Share #4 Posted October 10, 2013 The mirrors look superficially similar but are very subtly different in shape, are you sure you aren't inventing a conspiracy theory over what are just odd part numbers? Steve Different angle of view, mirrors are identical, only the post is different, one for left and one for right side. Not trying to invent a conspiracy theory but I was thinking that in converting from the Bayer array there might be some unexpected effect showing up here. Link to post Share on other sites More sharing options...
malsop Posted October 10, 2013 Author Share #5 Posted October 10, 2013 Never seen this so far but there seems to be a curious reflexion on the brick wall above the mirror as well. Would be interesting to process your file again with the same or preferably another raw converter. Here is a better view of the area I think you are referring to. In context this area looks right to me. A reflection off the windshield would not create a horizontal edge (top of the light colored faux brick) or vertical lines (near the window). Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! I also thought of trying a different converter but Leica ships LR which uses the same conversion engine as ACR so they must test with the Adobe converter. The only other converters I have installed are Nikon NX2 and C1. If I get the time I'll see what they do. Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! I also thought of trying a different converter but Leica ships LR which uses the same conversion engine as ACR so they must test with the Adobe converter. The only other converters I have installed are Nikon NX2 and C1. If I get the time I'll see what they do. ' data-webShareUrl='https://www.l-camera-forum.com/topic/214408-bad-conversion-from-raw/?do=findComment&comment=2438620'>More sharing options...
sandymc Posted October 10, 2013 Share #6 Posted October 10, 2013 Post the raw somewhere, and we can take a look at it. Sandy Link to post Share on other sites More sharing options...
01af Posted October 10, 2013 Share #7 Posted October 10, 2013 Advertisement (gone after registration) Post the raw somewhere, and we can take a look at it. Good idea. I think I can see at least two more spots with discontinuities. On the rear-view mirror's rim, they are just most obvious. The discontinuities seem to appear on a straight line which is not parallel to one of the frame's edges ... strange ... Link to post Share on other sites More sharing options...
Luke_Miller Posted October 10, 2013 Share #8 Posted October 10, 2013 Possibly aliasing? I've seen aliasing in some of my images. Invariably brightly lit chrome pieces. Link to post Share on other sites More sharing options...
malsop Posted October 10, 2013 Author Share #9 Posted October 10, 2013 Post the raw somewhere, and we can take a look at it. Sandy I've uploaded the file as it came out of the camera to.... zooroomphotography.com/zr_Private/_ChromeAberration/L1000211copy.DNG It is 30.1 MB Please post back what you find out ...Thanks Link to post Share on other sites More sharing options...
sandymc Posted October 10, 2013 Share #10 Posted October 10, 2013 Not a raw conversion artifact - this is what AccuRaw makes of it with all enhancements switched off. My best guess is that there is a discontinuity in whatever the chrome edges of the mirror are reflecting. Sandy Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/214408-bad-conversion-from-raw/?do=findComment&comment=2439126'>More sharing options...
malsop Posted October 11, 2013 Author Share #11 Posted October 11, 2013 Not a raw conversion artifact - this is what AccuRaw makes of it with all enhancements switched off. My best guess is that there is a discontinuity in whatever the chrome edges of the mirror are reflecting. Sandy Thanks for taking the time to check the raw file in a different conversion application and posting the results. Interpolating the final pixels from the Bayer pattern must use a heuristics algorithm which will make some assumptions. Looking at this particular visual anomaly I wondered if there might be situations where the general approach to designing the heuristic tree made inaccurate pixel computations. I think the best approach to unraveling this question would be to shoot a specific setup that produced the anomaly in camera with a Bayer patterned sensor and again with something like the Leica M Monochrome. If both cameras produced the same anomaly it would be a lighting issue. If only the Bayer sensor produced the anomaly it would be an interpolation issue. I'm intrigued since even the 300% enlargement is equivocal. Maybe I'll get an M Monochrome when I'm settled in Texas and play around with this a bit. I'm withholding judgement until a more definitive test can be made. Link to post Share on other sites More sharing options...
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