gpwhite Posted August 14, 2015 Share #1  Posted August 14, 2015 Advertisement (gone after registration) There have been a couple of threads about the wonderful 28 SX, some of which questioned its corrections for spatial distortion and chromatic aberrations. As a great admirer of this lens, I have found comments from Rick about CA and Jaap about spatial distortion to be particularly enlightening for me. Then, lct asked me to post examples of why I commented that the 28 SX shows both lateral and longitudinal chromatic aberrations. I have finally dug out one example from my first run of tests shot in order to decide if the 28 SX was worth keeping.  Two attributes of the 28 SX earned my approval immediately: zero spatial distortion (that I can perceive) and magnificent illumination corner-to-corner, even wide open. Also, my SX gives brighter colors than my 28 Summicron (since sold), so the SX is a masterpiece, for my taste. BTW, there are apparently certain review articles that question the sharpness or micro-contrast of this new lens... my 28 SX is in class with the 50 Summilux ASPH in this regard, and, if anything, slightly crisper than my 28 Summicron was.  I have whacked these files down to the restrictions of the forum, so I don't know how visible the defects will be. Crops inspect the central area, per lct's suggestion. You may notice in the exif that one file has ACR adjustments, while the other does not. I do not think that the adjustments I made (on the file that I wound up choosing to manipulate and print after my original tests) affect the main question here...  Both images are f/1.7. I noticed not only the prominent lateral CA (purple fringing) along the upper roof contrast edge, but also some fringing around the red reflector lens on the trailer near image center. I also find the gray spotlight fixture in the upper center to be less than clean, although this could be reflection of colors from elsewhere in the field of view onto the gray paint of the fixture. Per Rick's comment, I interpreted these centrally located fringes to be examples of longitudinal CA. Whatever actual sort of CA is evident on the red reflector, it is not possible to completely eliminate it, as one can for the lateral CA along the roof. I leave it to experts to categorize lateral or longitudinal origin, but these images do show CA near the optical axis of the lens.  I have other examples too, but they are essentially the same. The intent of my post is to show examples of fringing aberrations from the 28 SX. As Jaap commented somewhere, the optical formula for WA will always be a trade-off of control for CA vs. for spatial distortion. It strikes me that the 28 SX renders shapes beautifully, while it requires some post-processing clean up to deal with CA. I hope these are helpful  First, here is a copy of the image I printed. It is at f/2.4, which I found a little crisper. The "defect" versions follow. 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/248967-28-summilux-m-chromatic-aberrations/?do=findComment&comment=2871620'>More sharing options...
Advertisement Posted August 14, 2015 Posted August 14, 2015 Hi gpwhite, Take a look here 28 Summilux-M chromatic aberrations. I'm sure you'll find what you were looking for!
gpwhite Posted August 14, 2015 Author Share #2  Posted August 14, 2015 defect images 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/248967-28-summilux-m-chromatic-aberrations/?do=findComment&comment=2871623'>More sharing options...
mmradman Posted August 14, 2015 Share #3  Posted August 14, 2015 All that aberration technical mumbo jumbo is frankly well over my head I couldn't care less.  Your examples are excellent, we are looking at 28mm faster than F2, what a feat.  I found lens fabulous at any F stop and well above my photographic abilities but I enjoy learning it by the day.  Performance wise Elmarit R 28mm mk 2 springs to mind - unless it is swanky lens hood Link to post Share on other sites More sharing options...
gpwhite Posted August 14, 2015 Author Share #4  Posted August 14, 2015 All that aberration technical mumbo jumbo is frankly well over my head I couldn't care less.  Your examples are excellent, we are looking at 28mm faster than F2, what a feat.  I found lens fabulous at any F stop and well above my photographic abilities but I enjoy learning it by the day.  Performance wise Elmarit R 28mm mk 2 springs to mind - unless it is swanky lens hood  Thanks... I find the 28 Summilux to be just an incredible tool. It is even more nuanced, yet crispy, on the M246, perhaps because the MM has more natural snap?  I have shot a number of R, but not the lens you mention. If wanting maximum bite, then I shoot the 24 Elmarit-M ASPH (I carry these two WA and an APO 50). Images from both the 28 and the 24 need aberration washing, but their rendering is so good, it makes me look creative, . Link to post Share on other sites More sharing options...
CheshireCat Posted August 15, 2015 Share #5 Â Posted August 15, 2015 Thanks for posting. These are clear examples of longitudinal CA, clearly visible also at web resolution. Link to post Share on other sites More sharing options...
hiepphotog Posted August 15, 2015 Share #6 Â Posted August 15, 2015 Thank you for posting these. We can add coma into the list of aberrations this lens has. Do you see any Lateral CA(magenta on one side, cyan on the other)? Just to be clear, it would look like this: Â Link to post Share on other sites More sharing options...
gpwhite Posted August 15, 2015 Author Share #7 Â Posted August 15, 2015 Advertisement (gone after registration) Thank you for posting these. We can add coma into the list of aberrations this lens has. Do you see any Lateral CA(magenta on one side, cyan on the other)? Just to be clear, it would look like this: Â Â Well, if you look at the top of the full images I posted, where the blue roof tiles occlude the sky, you will see big swaths of CA in violet tones. I had the impression that this aberration was lateral CA. I have other images at f/5.6 in very bright light (perhaps EV 21 or 22, whatever the max the M240 will handle) where the violet fringing is also substantial. Massive amounts of ACR remove fringing is needed to clean this out. Â Just to be clear, I am not knocking down the 28 Summilux, which I cherish as a wonderful lens. I am just following up on my reply expressing surprise to an earlier comment where the OP stated this lens does not produce any CA. Well, as we all now show, it sure does! Link to post Share on other sites More sharing options...
jrp Posted August 15, 2015 Share #8 Â Posted August 15, 2015 Here's the Summmilux wide open at ISO 6400 (on a Sony body) taken as an experiment -- https://www.dropbox.com/s/38a7h4swynnieaj/20150811-235804_DSC00635.JPG?dl=0. Â For night shooting, I find that even (especially) the Noctilux is better stopped down and at ISO 100 for night shots, if you want a clean shot. Link to post Share on other sites More sharing options...
hiepphotog Posted August 15, 2015 Share #9 Â Posted August 15, 2015 Well, if you look at the top of the full images I posted, where the blue roof tiles occlude the sky, you will see big swaths of CA in violet tones. I had the impression that this aberration was lateral CA. I have other images at f/5.6 in very bright light (perhaps EV 21 or 22, whatever the max the M240 will handle) where the violet fringing is also substantial. Massive amounts of ACR remove fringing is needed to clean this out. Â Just to be clear, I am not knocking down the 28 Summilux, which I cherish as a wonderful lens. I am just following up on my reply expressing surprise to an earlier comment where the OP stated this lens does not produce any CA. Well, as we all now show, it sure does! Â I think you're right. LCA would not go away with stopping down (LoCA would). I don't think this is a bad lens at all. I'm just trying to justify replacing the Cron 28 with it . The Cron 28 is somewhat at odd with modern Leica draw. Link to post Share on other sites More sharing options...
jaapv Posted August 16, 2015 Share #10  Posted August 16, 2015 Thank you for posting these. We can add coma into the list of aberrations this lens has. Do you see any Lateral CA(magenta on one side, cyan on the other)? Just to be clear, it would look like this:  These shots are a Zeiss Planar on a Sony. I fail to see the relevance. Link to post Share on other sites More sharing options...
hiepphotog Posted August 16, 2015 Share #11  Posted August 16, 2015 These shots are a Zeiss Planar on a Sony. I fail to see the relevance. It's for demonstration of what LCA would look like. I didn't say this is from a Leica M-mount. Link to post Share on other sites More sharing options...
chanyr Posted August 17, 2015 Share #12 Â Posted August 17, 2015 Do you know if these aberrations will show up on film? Â Am planning to use this lens with a film M as well as digital. Link to post Share on other sites More sharing options...
gpwhite Posted August 17, 2015 Author Share #13 Â Posted August 17, 2015 Do you know if these aberrations will show up on film? Â Am planning to use this lens with a film M as well as digital. Â Some of the technically knowledgeable members will surely chime in here... Â but I would offer two comments in reply to your question. First, I have seen very strong CA on my Velvia images shot years ago with the APO-Elmarit-Makro 100mm on an R6.2. So the issue of chromatic aberration fringing in images is not limited to digital sensors, although it might be more prominent than with emulsion thickness at the focal plane. Second, and more important, I think you will find this issue can be provoked to some degree by the "right" circumstances with almost every lens. The 28 Summilux is a great lens and is not more prone to chromatic aberrations in my hands than the 28 Summicorn. Link to post Share on other sites More sharing options...
hiepphotog Posted August 17, 2015 Share #14 Â Posted August 17, 2015 ...Second, and more important, I think you will find this issue can be provoked to some degree by the "right" circumstances with almost every lens. The 28 Summilux is a great lens and is not more prone to chromatic aberrations in my hands than the 28 Summicorn. +1. Even with the APO, with a high contrast edge, if you push shadow enough in post, you will see purple fringing. Aberrations on Leica lenses are already very well corrected given the specs and size. Those, nitpick the point, are on the fence and trying to find an excuse not to buy, like me . Link to post Share on other sites More sharing options...
jrp Posted August 17, 2015 Share #15 Â Posted August 17, 2015 If you want aberration-free, fast, tiny lenses, i have not found any in the Leica range at least. Â The APO-50mm is as close as you are going to get. Link to post Share on other sites More sharing options...
Peter Branch Posted August 17, 2015 Share #16  Posted August 17, 2015 Can I take a very different view?  Leica long ago effectively eliminated all forms of CA in its wide angle lenses.  What is being complained about are properties of the sensor.  As I've posted elsewhere this is a highly complex subject which affects both film and digital sensors in different ways.  It follows that any lens can, in the right circumstances, appear to cause CA like artefacts.  It does seem that the effect on the sensor, film or digital, is to a degree modified by the overall correction of the other, usually monochromatic, aberrations - but it is not CA. Link to post Share on other sites More sharing options...
jrp Posted August 17, 2015 Share #17 Â Posted August 17, 2015 Whichever it is, it can make life hard wide open, on hard tonal transitions. Â Bokeh is, however, a different story (direct link:Â https://goo.gl/photos/qesFhrJtqZ16mdfc7) Link to post Share on other sites More sharing options...
Peter Branch Posted August 17, 2015 Share #18 Â Posted August 17, 2015 Whichever it is, it can make life hard wide open, on hard tonal transitions. Â Â Â Indeed it can. Link to post Share on other sites More sharing options...
CheshireCat Posted August 17, 2015 Share #19  Posted August 17, 2015 Leica long ago effectively eliminated all forms of CA in its wide angle lenses. What is being complained about are properties of the sensor.  Oh no, not again with this myth... Link to post Share on other sites More sharing options...
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