lct Posted March 26, 2015 Share #181 Posted March 26, 2015 Advertisement (gone after registration) Hi Henry, i can't seem to find any significant red or magenta fringing with Photoshop. Would you mind to post your crops? Link to post Share on other sites More sharing options...
Advertisement Posted March 26, 2015 Posted March 26, 2015 Hi lct, 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!
pgk Posted March 26, 2015 Share #182 Posted March 26, 2015 Somewhere I have files from my Canon 24/1.4 MkI lens which sufferers from a degree of CA. It shows high contrast, blown highlight, edge fringing too. If the fringing is CA how can it show CA twice? If I can find them I'll post samples but don't hold your breath. I am personally convinced that purple fringing is not a CA issue although confusion due to some CA being present can occur (as shown by my 24/1.4). The problem is that no amount of samples will actually 'prove' anything. They will simply reinforce a view/theory if a suitable explanation can be made to fit. And on that note when I shoot through a thick flat port underwater a variety of problems occur including clear and obvious CA, and again including fringing on high contrast edges with blown highlights. The two can be present together just as fringing can exist without CA so my view (not proven of course;)) is that fringing is not CA. Link to post Share on other sites More sharing options...
Doc Henry Posted March 26, 2015 Share #183 Posted March 26, 2015 Hi Henry, i can't seem to find any significant red or magenta fringing with Photoshop. Would you mind to post your crops? To test whether the aberration has disappeared crop 150% - original photo : 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! - after exposure (auto) correction (LR) : has just cleared the photo The aberration is still there in both cases Best Henry Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! - after exposure (auto) correction (LR) : has just cleared the photo The aberration is still there in both cases Best Henry ' 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=2787447'>More sharing options...
thighslapper Posted March 26, 2015 Share #184 Posted March 26, 2015 In Capture One there are two adjustments. One for Chromatic Aberration. One for Purple Fringing. The algorithms are different. Just an observation ..... draw your own conclusions ..... Link to post Share on other sites More sharing options...
CheshireCat Posted March 27, 2015 Share #185 Posted March 27, 2015 In Capture One there are two adjustments.One for Chromatic Aberration. One for Purple Fringing. The first one for "Chromatic Aberration" removes Lateral CA. The other removes the purple part of the Longitudinal CA. Note that Lightroom also has a third "Green Fringing" control to remove the green part of the Longitudinal CA. The term "Fringing" is used because most people don't know what Longitudinal CA is, as it is clear from the posts in this forum. draw your own conclusions ..... The conclusion is most people don't know that there are two distinct basic types of CA Link to post Share on other sites More sharing options...
CheshireCat Posted March 27, 2015 Share #186 Posted March 27, 2015 If the fringing is CA how can it show CA twice? Because there are two distinct basic types of CA, and they can both be present simultaneously. By the way, I am still waiting for your answers. Can't wait to be enlightened by your knowledge Link to post Share on other sites More sharing options...
jaapv Posted March 27, 2015 Share #187 Posted March 27, 2015 Advertisement (gone after registration) The first one for "Chromatic Aberration" removes Lateral CA. The other removes the purple part of the Longitudinal CA. Note that Lightroom also has a third "Green Fringing" control to remove the green part of the Longitudinal CA. The term "Fringing" is used because most people don't know what Longitudinal CA is, as it is clear from the posts in this forum. The conclusion is most people don't know that there are two distinct basic types of CA My conclusion is that most posters know exactly what the two types of CA are, but disagree with your rejection of the idea that anything digital could have anything to do with magenta fringing. (maybe because they know exactly what it is:rolleyes:) Link to post Share on other sites More sharing options...
thighslapper Posted March 27, 2015 Share #188 Posted March 27, 2015 Note that Lightroom also has a third "Green Fringing" control to remove the green part of the Longitudinal CA. not much green in evidence in most of these posts The term "Fringing" is used because most people don't know what Longitudinal CA is, as it is clear from the posts in this forum. So the folk at Capture Pro have labelled 'Longitudinal CA' as 'Purple fringeing' in a technically complex raw developer for advanced image manipulation because they think the users are too stupid to understand the difference .....??? You still have not explained how Longitudinal CA alone produces the aberrations in the images I posted previously. Please explain the marked discontinuity in the area concerned by optical aberrations alone. Everyone except you accepts that the sensor plays a part in images like this. That is all that is being argued here. No one is denying the part of CA (all aspects), but it is not the sole factor at play. 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=2787879'>More sharing options...
CheshireCat Posted March 27, 2015 Share #189 Posted March 27, 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. It also shows NO correlation between light intensity and sensor issues. This rules out blooming completely. It also shows NO correlation between sharp details and demosaic algorithm issues. This rules out software issues completely. Which other spooky sensor myths are left to debunk now ? 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. The difference can be easily explained because you used the APO 90/2, and Andy used the 35/2. The 90 is a longer FL, and LoCA is more visible at longer FL. The "APO" 90 (note the quotes) has very good correction for Lateral CA, but is disappointing about Longitudinal CA. In my opinion, the APO Summicron 90 should have never be called an APO lens by Leica's standards. I returned my copy and never looked back. Link to post Share on other sites More sharing options...
CheshireCat Posted March 27, 2015 Share #190 Posted March 27, 2015 not much green in evidence in most of these posts Green fringing is visible in some posts, but not easy to see for the untrained eye. The fact Capture One only has a "Purple Fringing" control is because of this, So the folk at Capture Pro have labelled 'Longitudinal CA' as 'Purple fringeing' in a technically complex raw developer for advanced image manipulation because they think the users are too stupid to understand the difference .....??? Yes. I also believe that the user manuals of many software image processing apps contain copy&paste explanations of CA from web sites spreading Internet myths. Software developers are not optical engineers, let alone people who write the manuals. You still have not explained how Longitudinal CA alone produces the aberrations in the images I posted previously. Please explain the marked discontinuity in the area concerned by optical aberrations alone. It is only visible in parts of the image containing intense high-frequencies (probably also UV and IR), in this case the white overexposed frame of the window which is directly reflecting sunlight. The fringing is only visible in the nearby dark areas (black cable), because: - It cannot be visible over the saturated white frame, as the sensor is already clipping on white. - It can be visible over a black non-reflective object (wire) because it is just an overlaid image of the purple component of the window frame, magnified and defocused by LoCA. Everyone except you accepts that the sensor plays a part in images like this. That is all that is being argued here. No one is denying the part of CA (all aspects) All your three sentences are false. Perhaps you should read posts more carefully. Link to post Share on other sites More sharing options...
lct Posted March 27, 2015 Share #191 Posted March 27, 2015 There is no such thing as "the cause" in causality chains, here and elsewhere. Should we repeat it like a mantra? Link to post Share on other sites More sharing options...
thighslapper Posted March 27, 2015 Share #192 Posted March 27, 2015 Green fringing is visible in some posts, but not easy to see for the untrained eye. Really ..... well you must have remarkable vision The fact Capture One only has a "Purple Fringing" control is because of this, Please provide a citation from Phase One for this. Yes. I also believe that the user manuals of many software image processing apps contain copy&paste explanations of CA from web sites spreading Internet mythsSoftware developers are not optical engineers, let alone people who write the manuals. Provide proof please. This is conjecture. Are you an Optical engineer ? It is only visible in parts of the image containing intense high-frequencies (probably also UV and IR), in this case the white overexposed frame of the window which is directly reflecting sunlight. The fringing is only visible in the nearby dark areas (black cable), because:- It cannot be visible over the saturated white frame, as the sensor is already clipping on white. - It can be visible over a black non-reflective object (wire) because it is just an overlaid image of the purple component of the window frame, magnified and defocused by LoCA. Proof please, this again is just your explanation and supposition. I am confused ...... is this a discussion or a a pedantry competition ? If you had a career in Politics you would go far, young man ..... Amusing as this is ..... I'm off to take pictures with my M and Petzval whilst the sun is out ...... all this talk about aberrations has reminded me how they can actually contribute positively to images ..... Link to post Share on other sites More sharing options...
CheshireCat Posted March 27, 2015 Share #193 Posted March 27, 2015 ^^^ thighslapper, [sigh] you are embarrassing yourself Study some good books about optical engineering (which I did), and stop posting disruptive comments containing zero or wrong information until you know something about the matter. Peace. Have a nice time taking pictures outside ! Link to post Share on other sites More sharing options...
pop Posted March 27, 2015 Share #194 Posted March 27, 2015 ... stop posting disruptive comments containing zero or wrong information until you know something about the matter. .... http://www.l-camera-forum.com/leica-forum/rules.php Link to post Share on other sites More sharing options...
CheshireCat Posted March 27, 2015 Share #195 Posted March 27, 2015 http://www.l-camera-forum.com/leica-forum/rules.php Yes, there are forum rules. Can you please explain why you cited all 8840 characters of text ? Link to post Share on other sites More sharing options...
pop Posted March 27, 2015 Share #196 Posted March 27, 2015 Yes, there are forum rules.Can you please explain why you cited all 8840 characters of text ? Sorry, this is a game I will not play. Link to post Share on other sites More sharing options...
jankap Posted March 28, 2015 Share #197 Posted March 28, 2015 for thighslapper In post 187 you publish the window frame picture again. The critical point is more or less in the center. Would it be possible to repeat this picture with the critical point far in one of the corners? In the corners the light rays hit under a different angle. Also a very much underexposed foto would be interesting. One, where the sunspot is exposed correctly, so to say. for cheshirecat Of course I am a dummy too, sorry for that. But if we want to diagnose a problem, we have to reconstruct it under given conditions. And we must show, that under the "opposite" conditions it does not show up. The "branches against the sky" is very different from a "sunspot in a window frame". Could both lead to the (in the first sight) same appearance? Jan (former Compuserve sysop) Link to post Share on other sites More sharing options...
Nordvik Posted March 28, 2015 Share #198 Posted March 28, 2015 Nokton 1,1/50: 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=2788596'>More sharing options...
Nordvik Posted March 28, 2015 Share #199 Posted March 28, 2015 Planar 2,0/50: 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=2788607'>More sharing options...
CheshireCat Posted March 28, 2015 Share #200 Posted March 28, 2015 Of course I am a dummy too, sorry for that. I think there are no dummy people here. Just people who are not informed enough, but think they are because they read something "on the Internet". They are easy to detect because they criticize, but if you ask them a question, they do not answer . Then there are "philosophers", those that can "justify" any point with nice tricks such as "the causality chain". Not dummy at all ! I do not have "the truth"; I am just reporting what I (and others) actually experience along with my deductions. I would like people to do the same. But if we want to diagnose a problem, we have to reconstruct it under given conditions. And we must show, that under the "opposite" conditions it does not show up. The "branches against the sky" is very different from a "sunspot in a window frame". Could both lead to the (in the first sight) same appearance? Makes sense, but unfortunately the opposite condition of "CA" is "no CA", and there are no lenses that have "no CA" (as you can see, even the top-notch APO Summicron 50 still suffers a bit from CA). Therefore, all we can prove is that a lens better corrected for CA has much less purple fringing under the exact same test conditions. Also note that there is nothing like "exact same", but there are nice approximations I think the "branches against the sky" and the "sunspot in a window frame" are not much different. Both involve a relatively dark out of focus object against a very bright background. I will replicate the same experiment and will keep you posted. Link to post Share on other sites More sharing options...
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