jaapv Posted March 25, 2015 Share #161 Posted March 25, 2015 Advertisement (gone after registration) Scroll down to the last set of pictures here:Chromatic aberrations Purple fringing on film. This should close the discussion for good. No, as it shows green counterfringing, making it lateral CA. Link to post Share on other sites More sharing options...
Advertisement Posted March 25, 2015 Posted March 25, 2015 Hi jaapv, Take a look here Is this CA problem on my 50/1.4 ASPH, it's normal or not?. I'm sure you'll find what you were looking for!
CheshireCat Posted March 25, 2015 Share #162 Posted March 25, 2015 No, as it shows green counterfringing, making it lateral CA. Like I said, the left image is lateral CA. The center and right images show longitudinal CA. Link to post Share on other sites More sharing options...
Doc Henry Posted March 25, 2015 Share #163 Posted March 25, 2015 Cheshire I have some knowledge in optical physics, I think CA could be caused by the light source ie projection lamp which emits white light composed as you know of different wavelengths ranging from violet to red , hence my answer ! Best Henry Link to post Share on other sites More sharing options...
Nordvik Posted March 25, 2015 Share #164 Posted March 25, 2015 Film/Digital: 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/242349-is-this-ca-problem-on-my-5014-asph-its-normal-or-not/?do=findComment&comment=2787044'>More sharing options...
BerndReini Posted March 25, 2015 Share #165 Posted March 25, 2015 Hard to tell anything from film pictures. Digital is just so much cleaner that CA shows much more. I guess we can all agree that some lenses show more purple fringing than others, but this doesn't take anything away from the 50lux - hands down the best designed lens with regard to performance, size, and speed combined from any manufacturer. Link to post Share on other sites More sharing options...
Nordvik Posted March 25, 2015 Share #166 Posted March 25, 2015 Film/Digital: 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/242349-is-this-ca-problem-on-my-5014-asph-its-normal-or-not/?do=findComment&comment=2787069'>More sharing options...
jaapv Posted March 25, 2015 Share #167 Posted March 25, 2015 Advertisement (gone after registration) Like I said, the left image is lateral CA.The center and right images show longitudinal CA. Not if you look in the A channel of LAB, a bit of manipulating will show up the counterfringe. Link to post Share on other sites More sharing options...
Peter Branch Posted March 25, 2015 Share #168 Posted March 25, 2015 Nordvik; please can you tell us the technical information about the pictures. In particular what film was used? Thanks in advance. Link to post Share on other sites More sharing options...
Nordvik Posted March 25, 2015 Share #169 Posted March 25, 2015 Portra 160. Scanner Nikon 4000. Camera IIIc & M8. Lens 3,5/50 Elmar (could be Planar 2,0/50 ZM with M8 on the first pair, it has been more than two years and I am not sure). Link to post Share on other sites More sharing options...
wlaidlaw Posted March 25, 2015 Share #170 Posted March 25, 2015 Slightly off at a tangent but I was told by the guys on the Kodak Stand at Photokina, that Ektar 100 colour negative film was getting near to 200 lp/mm resolution, which if my arithmetic still works, is around 34.5 MP equivalent for a 35mm negative. So the argument that film does not resolve to the level that could show fringing, if you were using the correct film, would not be valid. Even allowing Kodak to be exaggerating somewhat (I thought it was only othrographic film that reached that level of resolution), it might still resolve to at least the level of the M9 sensor, which can easily show fringing. In the absence of people posting film images showing fringing, does this not mean that fringing is a wholly sensor driven phenomenon not lens. I use Ektar 100 in my M4 with the Zeiss ZM Planar 50, which Zeiss also claim to be able to resolve to 200 lp/mm and I have never detected fringing on any recent film images. Wilson Link to post Share on other sites More sharing options...
CheshireCat Posted March 26, 2015 Share #171 Posted March 26, 2015 Portra 160. Scanner Nikon 4000. Camera IIIc & M8. Lens 3,5/50 Elmar (could be Planar 2,0/50 ZM with M8 on the first pair, it has been more than two years and I am not sure). Thanks for your contribution. I see these problems with your test images: - The digital shots are overexposed and the film shots are not. We all know that overexposure makes CA much more visible. - Your film scanner introduces a huge amount of digital noise that is dithering and washing out colors. - The film resolution is so poor that grain may be smoothing CA quite a bit. the tree foliage is quite desaturated, almost B&W. - The tree foliage shot shows multicolored artifacts that may be caused by moire and/or JPEG compression. Do you have the RAW file ? Link to post Share on other sites More sharing options...
CheshireCat Posted March 26, 2015 Share #172 Posted March 26, 2015 Not if you look in the A channel of LAB, a bit of manipulating will show up the counterfringe. I am eagerly waiting for your image revealing the magic invisible counterfringe Link to post Share on other sites More sharing options...
jaapv Posted March 26, 2015 Share #173 Posted March 26, 2015 You'll have to try it yourself. I'm on my way to Italy for the last of the season's skiing and my laptop is limited to LR. Maybe in a few weeks.... Link to post Share on other sites More sharing options...
Exodies Posted March 26, 2015 Share #174 Posted March 26, 2015 I performed Cheshire's experiment (quoted below) using an M240 and APO-Summicron-M 1:2/90 ASPH. The reduction of purple haze is enormous going from f2 to f8. However, this only demonstrates correlation between lens configuration and purple haze and as we all know, correlation doesn't imply chirping mustard. The difference between my two samples is much greater than the difference between two of Adan's samples 4 stops apart. This might be a clue to something but it's still only correlation. I will post my results if anyone says "kerpow". Stopping down does not reduce the amount of light, provided you compensate the exposure time accordingly.This easy test can show you the sensor has nothing to do with PF: - Camera on a tripod. - Frame tree branches. - Focus so that most branches are in front of the focus field (i.e. focus behind the branches). - Overexpose wide open (e.g. 1/2000s@f/2), - Take the photo, and make sure you see PF. - Do not re-focus. - Stop down 4 stops and set the equivalent overexposure (e.g. 1/125s@f/8). - Take the photo, and verify that PF is gone (or dramatically reduced) even if the amount of light striking the sensor is the same. Link to post Share on other sites More sharing options...
Mornnb Posted March 26, 2015 Share #175 Posted March 26, 2015 Hard to tell anything from film pictures. Digital is just so much cleaner that CA shows much more. I guess we can all agree that some lenses show more purple fringing than others, but this doesn't take anything away from the 50lux - hands down the best designed lens with regard to performance, size, and speed combined from any manufacturer. Leica cameras do not have an anti-aliasing filter. The advantage of this is greater sharpness. The disadvantage is for small edges and very sharp lenses, they may only fall on pixels of certain colours, giving the edges of thin lines a coloured tone. I performed Cheshire's experiment (quoted below) using an M240 and APO-Summicron-M 1:2/90 ASPH. The reduction of purple haze is enormous going from f2 to f8. However, this only demonstrates correlation between lens configuration and purple haze and as we all know, correlation doesn't imply chirping mustard.. Try going all the way up to f16. If this is an issue with the bayer filter as I've suggested, diffraction should induce blur which should remove the purple fringing. The problem may be that the lens is too sharp, 24MP ain't enough for these lenses. Link to post Share on other sites More sharing options...
Exodies Posted March 26, 2015 Share #176 Posted March 26, 2015 I could have been clearer The purple is already gone by f8. Link to post Share on other sites More sharing options...
lct Posted March 26, 2015 Share #177 Posted March 26, 2015 Interesting to compare with Foveon sensors here: http://www.yaotomi.co.jp/blog/walk/DP3Q0155b.jpg (29MB file) Link to post Share on other sites More sharing options...
Doc Henry Posted March 26, 2015 Share #178 Posted March 26, 2015 Interesting to compare with Foveon sensors here:http://www.yaotomi.co.jp/blog/walk/DP3Q0155b.jpg (29MB file) Lct ,as you know , Foveon sensor is remarkable because it has 3 layers (RGB) like film Best Henry Link to post Share on other sites More sharing options...
lct Posted March 26, 2015 Share #179 Posted March 26, 2015 Do you think the cyan/blue tint of the fringing comes from the third layer? Link to post Share on other sites More sharing options...
Doc Henry Posted March 26, 2015 Share #180 Posted March 26, 2015 Lct I tried on LR to adjust the WB, the exposure correction and the two crops show a purple color aberration at the edges of leaves,which proves that it "probably" comes from sensor or lenses. Best Henry Link to post Share on other sites More sharing options...
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