thighslapper Posted March 20, 2015 Share #81 Posted March 20, 2015 Advertisement (gone after registration) How sad is your attitude.You don't even know the definition of "faith". Please react This is getting insulting and I am not rising to the bait. I think you need to reconsider your own attitude if you wish to contribute constructively to this forum in future. I'm off. Link to post Share on other sites More sharing options...
Advertisement Posted March 20, 2015 Posted March 20, 2015 Hi thighslapper, 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!
BerndReini Posted March 20, 2015 Share #82 Posted March 20, 2015 Purple fringing seems to be mainly a problem resulting from wavelengths of the invisible spectrum. I believe that lens design has come to its apex and new solutions in how to deal with the "invisible" (to the eye) spectrum will happen on the sensor front. We have long reached a point of diminishing return. Btw. The Sony A7 in combination with the 50 1.8 shows horrible purple fringing. And just as an aside from someone who has been on this forum for a long time: Cheshire Cat, you are guilty of what you accuse other people of and it does come across as a little arrogant. I am not attacking you and I am pretty neutral here and see where you are coming from, but just realize that when Jaap and I get into it for example, we have known each other on this forum for a long time. This is a pretty cool forum and you could be a little more tactful yourself. Things come across the wrong way when people aren't face to face. Agreed? Your move toward thighslapper. Link to post Share on other sites More sharing options...
lct Posted March 21, 2015 Share #83 Posted March 21, 2015 Peace folks . World class techies of this forum seem to agree that purple fringing results from a combination of causes including blown highlights, digital sensors and CA in whatever order/priority anyone prefers. I still don't understand why there is no purple fringing on film but i can live with that. Link to post Share on other sites More sharing options...
Winedemonium Posted March 21, 2015 Share #84 Posted March 21, 2015 I don't think I will mention to anyone later this evening what I just spent 20 minutes reading. I do like these threads but usually feel a little wiser and a lot more confused at the end of reading them: a mental one step forward, two steps back. Link to post Share on other sites More sharing options...
jrp Posted March 21, 2015 Share #85 Posted March 21, 2015 Whatever it is, it is a function of the lens, and not just the sensor or demosaicing. If you look at digilloyd's direct comparison of the 21mm Summilux and Super-Elmarit, at f3.4, for example, the Summilux shows the purple fringing at very high contrast edges where the Super-Elmarit does not. Link to post Share on other sites More sharing options...
pgk Posted March 21, 2015 Share #86 Posted March 21, 2015 Whatever it is, it is a function of the lens, and not just the sensor or demosaicing. If you look at digilloyd's direct comparison of the 21mm Summilux and Super-Elmarit, at f3.4, for example, the Summilux shows the purple fringing at very high contrast edges where the Super-Elmarit does not. This does NOT mean that its simply a function of the lens. It can be as easily interpreted as being a function of both lens and sensor. Comparing two very different lenses in this way may well not tell us anything other than that they are different. That said, I would actually expect a boundary-pushing design to produce different images from a lens with a much more conventional specification and this is likely to be true at the same aperture. The interaction between the image formed by the lens on the sensor and the sensor is, as I have said before, likely to be complicated and explaining something in simplistic terms may well lead to false conclusions. There are some here who are determined that everything should have a straightforward explanation, but reality is often not like that. Link to post Share on other sites More sharing options...
jrp Posted March 21, 2015 Share #87 Posted March 21, 2015 Advertisement (gone after registration) This does NOT mean that its simply a function of the lens. I did NOT say that it was. Link to post Share on other sites More sharing options...
viramati Posted March 21, 2015 Share #88 Posted March 21, 2015 Unfortunately the lux 50 asph is not a great performer on the A7mkI, mkII or the A7s (not that this issue is anything to do with the A7) with considerable smearing towards the edges. Best normal lens on the Sony is the FE55/1.8 which is superb. Link to post Share on other sites More sharing options...
lct Posted March 21, 2015 Share #89 Posted March 21, 2015 The smearing issue has nothing to do with the Summilux for sure and no Sony body has been made to use RF lenses because Sony did not want so. By comparison, my Fuji X-E2 has certainly to do with the smeared corners it shows with 28 or 21mm M lenses whilst the Ricoh GXR is perfect with the latters. Link to post Share on other sites More sharing options...
pgk Posted March 21, 2015 Share #90 Posted March 21, 2015 I did NOT say that it was. Sorry. This is how I read your post and I obviously got it wrong:rolleyes:. Link to post Share on other sites More sharing options...
CheshireCat Posted March 21, 2015 Share #91 Posted March 21, 2015 What evidence do you have for this assertion? The evidence is that Zeiss and Leica cannot call the lens "apochromatic" if it is "achromatic". Are you telling me that both Zeiss and Leica are cheating ? Link to post Share on other sites More sharing options...
CheshireCat Posted March 21, 2015 Share #92 Posted March 21, 2015 This is getting insulting and I am not rising to the bait. I think you need to reconsider your own attitude if you wish to contribute constructively to this forum in future. I'm off. I am sorry if you feel insulted. My harsh reply was the result of you dismissing my explanations as "faith" (which is quite insulting, but I am not easily offended). Link to post Share on other sites More sharing options...
CheshireCat Posted March 21, 2015 Share #93 Posted March 21, 2015 This does NOT mean that its simply a function of the lens. It can be as easily interpreted as being a function of both lens and sensor. I think we all agree on the fact that digital sensors amplify the intensity of this problem with respect to film. To recap: - The cause of this issue is CA. - The intensity of the issue is very noticeable because of the properties of digital sensors, making it much more noticeable than on film. Link to post Share on other sites More sharing options...
lct Posted March 21, 2015 Share #94 Posted March 21, 2015 Funnily enough it was taking a picture of that same tree later in the year, when it was covered in blossom, which convinced me to get rid of my particular 50 ASPH Summilux. I cannot find the original M8 DNG but only the JPEG, which I had corrected to get rid of most of the fringing. The JPEG does not look any more over-exposed than the SEM 18mm pictures... Would have been interesting to compare them to my ones below. 50/1.4 asph, f/5.6, 1/500s & 1/60s, no fringing correction. 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=2784705'>More sharing options...
CheshireCat Posted March 21, 2015 Share #95 Posted March 21, 2015 Would have been interesting to compare them to my ones below. 50/1.4 asph, f/5.6, 1/500s & 1/60s, no fringing correction. And this demonstrates that - like I said multiple times - purple fringing happens in front of the focus field and CA is minimized by stopping down. If the sensor was the cause, your shot would have plenty of purple fringing, but... uh oh... there is none Link to post Share on other sites More sharing options...
pgk Posted March 21, 2015 Share #96 Posted March 21, 2015 I think we all agree on the fact that digital sensors amplify the intensity of this problem with respect to film. To recap: - The cause of this issue is CA. - The intensity of the issue is very noticeable because of the properties of digital sensors, making it much more noticeable than on film. I'm sorry but I must be missing something here. Are you reading the same (this) thread as I am? The cause is most certainly not CA (although it may contribute its own input to an image too, thus complicating matters) as has been demonstrated in this and many other threads. The intensity of the problem is obviously amplified on digital sensors as opposed to film because it doesn't exist on film (unlike CA which most certainly does). If you look at the OP image you will also see that the problem shows up fairly centrally in the image - not really where CA would be expected to show up significantly is it? Link to post Share on other sites More sharing options...
CheshireCat Posted March 21, 2015 Share #97 Posted March 21, 2015 Are you reading the same (this) thread as I am? Yes. Most of the posts are mine The cause is most certainly not CA (although it may contribute its own input to an image too, thus complicating matters) as has been demonstrated in this and many other threads. It has never been demostrated in this and any other threads (or web site) that the cause is the sensor, while it has been demostrated that the cause is CA. If you are not able to demostrate it, at least you should refer to a post that clearly does. If you look at the OP image you will also see that the problem shows up fairly centrally in the image - not really where CA would be expected to show up significantly is it? There are two different kinds of CA: lateral and longitudinal. Lateral CA is absent on the axis (center of the image) and increases with the distance from the center. That is the one you are talking about. But the second type, Longitudinal CA, is a different beast and can show up significantly in the center of the image. Link to post Share on other sites More sharing options...
pgk Posted March 21, 2015 Share #98 Posted March 21, 2015 But the second type, Longitudinal CA, is a different beast and can show up significantly in the center of the image. OK, explain to me how, in the OP's first centre crop, Longitudinal CA can vary, in terms of its apparent pixel width, within a small portion of the image. I do suspect though that I might as well find a brick wall to hit my head against..... Link to post Share on other sites More sharing options...
CheshireCat Posted March 21, 2015 Share #99 Posted March 21, 2015 OK, explain to me how, in the OP's first centre crop, Longitudinal CA can vary, in terms of its apparent pixel width, within a small portion of the image. I do suspect though that I might as well find a brick wall to hit my head against..... I explain that by more high-frequency light being reflected by these areas. Your turn now. Explain that in terms of digital sensor issues. It is funny to note that I asked several questions to a lot of people in this thread, and no one dared to provide an answer Link to post Share on other sites More sharing options...
lct Posted March 21, 2015 Share #100 Posted March 21, 2015 It is funny to note that I asked several questions to a lot of people in this thread, and no one dared to provide an answer[/b][/color] Really? Why do you think that the out of focus cable purple fringing is caused by the sensor ? Because i have never seen that on film. And i still don't understand why. As well as i don't understand how a lens with little CA like the 50/1.4 asph can do purple fringing if CA is the primary or even the sole (?) cause of the latter. Link to post Share on other sites More sharing options...
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