lct Posted May 17, 2021 Share #41 Posted May 17, 2021 Advertisement (gone after registration) 12 minutes ago, pedaes said: Geez - what is this all about? Use the lenses that give you what you want. For the record, the APO-90 Summicron is a APO lens. Think your issue comes not from the lens. Too bad for Loca/Laca but so much the better for Leica . I often use my 90/2 apo on a Kolari mod A7r2 and I've yet to see the OP's issue to be honest. Now fact is the Kolari UT (for ultra thin) filter has some effect on colors. Would be interesting to dig into that perhaps. 1 Quote Link to post Share on other sites More sharing options...
Advertisement Posted May 17, 2021 Posted May 17, 2021 Hi lct, Take a look here 90mm Apo-Summicron-M not apochromatic?. I'm sure you'll find what you were looking for!
LarsHP Posted May 17, 2021 Author Share #42 Posted May 17, 2021 13 minutes ago, lct said: Too bad for Loca/Laca but so much the better for Leica . I often use my 90/2 apo on a Kolari mod A7r2 and I've yet to see the OP's issue to be honest. Now fact is the Kolari UT (for ultra thin) filter has some effect on colors. Would be interesting to dig into that perhaps. Okay! So you also use it with a Kolari UT modded camera! Regarding colors, since tests with Sony a7 series cameras have shown significant changes in color reproduction, I bought an X-Rite ColorChecker chart and have calibrated the camera using their software. In other words, colors should be spot on now. (As an aside, I can report that auto white balance works quite fine on my Z6UT.) Since you haven't seen anything like that in my sample in the OP, I should say that this is also something I haven't seen previously - at least not as strongly. It may be the combination of sun and snow-earth transitions + focus at medium distance with a background far away which has provoked the lens to show quite strong LoCA which otherwise doesn't happen. I will of course investigate it more and if it's a one in a thousand issue, then I will probably keep the lens. Quote Link to post Share on other sites More sharing options...
jaapv Posted May 17, 2021 Share #43 Posted May 17, 2021 You are right there - it is incorrect to judge a lens separately from the sensor, it is an interdependent imaging system. I can well imagine a cover glass creating lateral CA, longitudinal is of course a bit more complicated. An then we have the design of the microlenses. The SL sensors have a specific higher shape to reduce crosstalk on M lenses, for instance. When you use an adapted "foreign" sensor on an M lens, all bets are off. It will give the best results on an M sensor (and specifically designed sensors like SL). Period. 28 minutes ago, lct said: Too bad for Loca/Laca but so much the better for Leica . I often use my 90/2 apo on a Kolari mod A7r2 and I've yet to see the OP's issue to be honest. Now fact is the Kolari UT (for ultra thin) filter has some effect on colors. Would be interesting to dig into that perhaps. . 3 Quote Link to post Share on other sites More sharing options...
jaapv Posted May 17, 2021 Share #44 Posted May 17, 2021 4 minutes ago, LarsHP said: Okay! So you also use it with a Kolari UT modded camera! Regarding colors, since tests with Sony a7 series cameras have shown significant changes in color reproduction, I bought an X-Rite ColorChecker chart and have calibrated the camera using their software. In other words, colors should be spot on now. (As an aside, I can report that auto white balance works quite fine on my Z6UT.) Since you haven't seen anything like that in my sample in the OP, I should say that this is also something I haven't seen previously - at least not as strongly. It may be the combination of sun and snow-earth transitions + focus at medium distance with a background far away which has provoked the lens to show quite strong LoCA which otherwise doesn't happen. I will of course investigate it more and if it's a one in a thousand issue, then I will probably keep the lens. Borrow an M10 or SL2 and try it out properly. 1 Quote Link to post Share on other sites More sharing options...
ianman Posted May 17, 2021 Share #45 Posted May 17, 2021 18 minutes ago, LarsHP said: I will of course investigate it more Looking forward to reading your reports! 1 Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #46 Posted May 17, 2021 8 minutes ago, jaapv said: Borrow an M10 or SL2 and try it out properly. Now, if I was testing a wide angle or even a normal lens, then we fully agree that I should test it on an M camera. However, we are talking about a 90mm lens, and so far I haven't seen anyone seeing problems with 90mm lenses on sensors with thick cover glass. Angles of light goes relatively right on into the pixel wells. My Z6UT has about the same total thickness as an M camera, so there is little to suggest that it's the sensor that is the problem. As mentioned above, my Z6UT actually behaves better than the M 240 regarding odd colors ("Italian flag") and I see no color shift with the 90mm apo - not now and neither before the Kolari UT service. Quote Link to post Share on other sites More sharing options...
ianman Posted May 17, 2021 Share #47 Posted May 17, 2021 (edited) Advertisement (gone after registration) 10 minutes ago, LarsHP said: My Z6UT has about the same total thickness as an M camera, so there is little to suggest that it's the sensor that is the problem. As mentioned above, my Z6UT actually behaves better than the M 240 regarding odd colors ("Italian flag") There is more to sensor design than it's thickness. The fact that you are not seeing the italian flag effect on one and not the other should be a clue. https://the.me/the-leica-m-max-sensor-explained/ Edited May 17, 2021 by ianman Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #48 Posted May 17, 2021 In case anyone can't see or find what I am talking about, here's a tight crop of the image in the OP. It's in the midframe, so I find it heard to believe that it has anything to do with the sensor. (In fact, since the Z6 has a back side illuminated sensor, its pixel wells are more "open" than previous types.) 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! 1 Quote 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/320955-90mm-apo-summicron-m-not-apochromatic/?do=findComment&comment=4202420'>More sharing options...
LarsHP Posted May 17, 2021 Author Share #49 Posted May 17, 2021 1 minute ago, ianman said: There is more to sensor design than it's thickness. The fact that you are not seeing the italian flag effect on one and not the other should be a clue. Right, but the reason that it doesn't show as much "Italian flag" with the 28mm Summicron-M Asph II is that the Z6 has a back side illuminated sensor, its pixel wells are more "open" than previous types (as I wrote while you typed your comment). This suggests that the Z6UT should have less issues, not more. And regarding a 90mm, it won't matter at all. Quote Link to post Share on other sites More sharing options...
jaapv Posted May 17, 2021 Share #50 Posted May 17, 2021 12 minutes ago, LarsHP said: In case anyone can't see or find what I am talking about, here's a tight crop of the image in the OP. It's in the midframe, so I find it heard to believe that it has anything to do with the sensor. (In fact, since the Z6 has a back side illuminated sensor, its pixel wells are more "open" than previous types.) 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! Normally CA is green/red and-or blue/purple. That it is green-purple here is strange. I would rule out a sensor effect by testing on a proprietary sensor in any case. As you say, that the effect is in the center and on a 90 mm lens makes the likelihood of incidence angle problems less, but the sensor-lens projection interface is quite a bit more subtle than that. BTW, the larger receiving surface of a BSI sensor does make it more sensitive to crosstalk. 1 Quote Link to post Share on other sites More sharing options...
ianman Posted May 17, 2021 Share #51 Posted May 17, 2021 38 minutes ago, jaapv said: That it is green-purple here is strange. "Longitudinal chromatic aberrations or LoCAs are ugly purple and green fringing seen in the out of focus areas in front of and behind the focus point of an image." https://www.closeuphotography.com/loca-test/ 1 1 Quote Link to post Share on other sites More sharing options...
jaapv Posted May 17, 2021 Share #52 Posted May 17, 2021 That is not my experience - it is mostly blue or purple. The article you link to is aimed at close-up photography and not near-infinity like in this thread. Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #53 Posted May 17, 2021 2 hours ago, jaapv said: (...) I would rule out a sensor effect by testing on a proprietary sensor in any case. As you say, that the effect is in the center and on a 90 mm lens makes the likelihood of incidence angle problems less, but the sensor-lens projection interface is quite a bit more subtle than that. BTW, the larger receiving surface of a BSI sensor does make it more sensitive to crosstalk. If you check the image I linked to in post #29, it is quite obvious that the lens performs pretty flawlessly at infinity. It's shot at f/2 and practically everything from corner to corner looks as sharp as expected from a top performing lens shot wide open. This rules out that it's a lens-sensor issue. Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #54 Posted May 17, 2021 (edited) Okay. New test shots. Here comparing the 90mm Apo-Summicron-M (#1) versus the Elmarit-M (#2)and 180mm Apo-Lanthar (#3). All shot wide open and purposely defocused in order to show LoCA handling where it looks the worst. Crops are in 100% and from the very center of the frame. The Elmarit-M is not far behind the Apo-Summicron-M when both are shot wide open even though it's a non-apo lens designed for film. The Voigtländer looks pretty perfect to me. 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! Edited May 17, 2021 by LarsHP 1 Quote 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/320955-90mm-apo-summicron-m-not-apochromatic/?do=findComment&comment=4202506'>More sharing options...
pedaes Posted May 17, 2021 Share #55 Posted May 17, 2021 Bingo! You have found your perfect lens. Enjoy! 7 minutes ago, LarsHP said: The Voigtländer looks pretty perfect to me. Bingo! You have found your perfect lens. Enjoy! 1 1 Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #56 Posted May 17, 2021 2 hours ago, jaapv said: That is not my experience - it is mostly blue or purple. The article you link to is aimed at close-up photography and not near-infinity like in this thread. I think the exact colors in LoCA may depend on the lens; how it handles/focuses the different wavelengths in front/behind the plane of focus. Check here: https://www.colesclassroom.com/what-is-chromatic-aberration-and-how-can-you-avoid-it/ Quote: "In the case of LoCA, there’s usually red, green, and blue fringing throughout the image." And here: https://www.photoaspects.com/what-is-chromatic-aberration/ Quote: "In the image, it usually manifests itself as a blurred green or purple fringe." In my experience it's usually green and purple. 1 Quote Link to post Share on other sites More sharing options...
LarsHP Posted May 17, 2021 Author Share #57 Posted May 17, 2021 (edited) 4 minutes ago, pedaes said: Bingo! You have found your perfect lens. Enjoy! Right. But it's a 180mm. I need a short telephoto lens too. Edited May 17, 2021 by LarsHP Quote Link to post Share on other sites More sharing options...
Robert Blanko Posted May 17, 2021 Share #58 Posted May 17, 2021 (edited) vor 3 Stunden schrieb LarsHP: In case anyone can't see or find what I am talking about, here's a tight crop of the image in the OP. It's in the midframe, so I find it heard to believe that it has anything to do with the sensor. (In fact, since the Z6 has a back side illuminated sensor, its pixel wells are more "open" than previous types.) 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! IMHO, this cannot be the result of only LoCas, as they usually have a color depending on whether the object is in front or behind the focus plane (cf. also the link in ianman‘s post) - whereas here the objects seem to be located in the same plane but there are nevertheless two colors. https://diglloyd.com/prem/s/MSI/publish/Optical-LOCA-secondary.htmlhttps://diglloyd.com/prem/s/MSI/publish/Optical-LOCA-secondary.html Edited May 17, 2021 by Robert Blanko Quote Link to post Share on other sites More sharing options...
ianman Posted May 17, 2021 Share #59 Posted May 17, 2021 20 minutes ago, LarsHP said: I think the exact colors in LoCA may depend on the lens; how it handles/focuses the different wavelengths in front/behind the plane of focus. Check here: https://www.colesclassroom.com/what-is-chromatic-aberration-and-how-can-you-avoid-it/ Quote: "In the case of LoCA, there’s usually red, green, and blue fringing throughout the image." And here: https://www.photoaspects.com/what-is-chromatic-aberration/ Quote: "In the image, it usually manifests itself as a blurred green or purple fringe." In my experience it's usually green and purple. Green and purple here and here and many others, but sometimes it's best not to question the word of god. 1 1 Quote Link to post Share on other sites More sharing options...
ianman Posted May 17, 2021 Share #60 Posted May 17, 2021 25 minutes ago, LarsHP said: Right. But it's a 180mm. I need a short telephoto lens too. It can be easily arranged... 3 Quote Link to post Share on other sites More sharing options...
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