CheshireCat Posted February 16, 2016 Share #301 Posted February 16, 2016 Advertisement (gone after registration) New interesting thing I have found while testing my "brand new" Summicron-M 90. Notice that the sensor is totally saturated in the white area, yet segmented purple fringing. The UV CA is my theory. What do you guys think ? 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=2990955'>More sharing options...
Advertisement Posted February 16, 2016 Posted February 16, 2016 Hi CheshireCat, 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!
lct Posted February 16, 2016 Share #302 Posted February 16, 2016 The 90/2 v3 is reknown for having more CA than both v2 and apo 90/2 lenses but i like much its softer rendition at f/2 which make it my favorite 90 for portrait with the R 90/2 pre-apo as well. Link to post Share on other sites More sharing options...
CheshireCat Posted February 16, 2016 Share #303 Posted February 16, 2016 The 90/2 v3 is reknown for having more CA than both v2 and apo 90/2 lenses but i like much its softer rendition at f/2 which make it my favorite 90 for portrait with the R 90/2 pre-apo as well. My copy is quite sharp. A much better lens quality/price wise than the nonsensical "APO" 90/2. Oh, and wonderful colors. Love this lens. Link to post Share on other sites More sharing options...
lct Posted February 17, 2016 Share #304 Posted February 17, 2016 I have both and the apo is significantly sharper at f/2. My not so young female models don't like it at all. Too sharp for them but "nonsensical"? i don't know what you nean sorry. Link to post Share on other sites More sharing options...
CheshireCat Posted February 17, 2016 Share #305 Posted February 17, 2016 I have both and the apo is significantly sharper at f/2. My not so young female models don't like it at all. Too sharp for them but "nonsensical"? i don't know what you nean sorry. Money-wise nonsensical Link to post Share on other sites More sharing options...
lct Posted February 17, 2016 Share #306 Posted February 17, 2016 Haha yes but it has never been more expensive than Leica lenses like 50/1.4 asph or 28/2 asph as far as i recall. Link to post Share on other sites More sharing options...
Rick Posted February 17, 2016 Share #307 Posted February 17, 2016 Advertisement (gone after registration) Simple LoCA, with the same effect we have seen in previous photos here when the bright background creates a sort of penumbra shadow effect. Rick Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2016 Share #308 Posted February 17, 2016 New interesting thing I have found while testing my "brand new" Summicron-M 90. Notice that the sensor is totally saturated in the white area, yet segmented purple fringing. The UV CA is my theory. What do you guys think ? The lens does not transmit any UV light to mention - I tried to do UV photography way back on the M8. The only lens that would produce an image was the Summarit 1.5/5 cm. All more modern lenses are UV opaque to a large extent - they will only show UV transmission ine extreme cases ( say- bright sunlight at an altitude over 3000 m.) Link to post Share on other sites More sharing options...
pgk Posted February 17, 2016 Share #309 Posted February 17, 2016 The lens does not transmit any UV light to mention - I tried to do UV photography way back on the M8. The only lens that would produce an image was the Summarit 1.5/5 cm. All more modern lenses are UV opaque to a large extent - they will only show UV transmission ine extreme cases ( say- bright sunlight at an altitude over 3000 m.) FWIW I had the rear two elements on a 35mm Summicron v.4 re-cemented after they had separated. The person who did this used a UV cured modern lens cement, but the report with the doublet when it came back stated that the lens had taken a high dose of UV to cure the adhesive due to its poor transmission of UV - obviously 'modern' goes back a fair time with regards to UV opacity of Leica lenses. Link to post Share on other sites More sharing options...
CheshireCat Posted February 17, 2016 Share #310 Posted February 17, 2016 The lens does not transmit any UV light to mention What about I/R then ? Or how do you explain the dashed line CA pattern ? Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2016 Share #311 Posted February 17, 2016 I have no explanation other than the sensor blooming/CA ones we have seen regularly on this forum. The contrast gradient is less on the less fringed parts, though. But all Leica lenses since the mid-1950ies have been constructed with UV filtering incorporated, either by adding Absorban to the lens cement or by coatings (e.g. Elmarit-M 90). in case there is no cemented element. I don't think IR would produce blue fringes. Link to post Share on other sites More sharing options...
Rick Posted February 17, 2016 Share #312 Posted February 17, 2016 Or how do you explain the dashed line CA pattern ? That is the shadow on the sensor from the edge of the blind with the bright light from the LoCA over falling the shadow like a penumbra. There is no bright light in the "dashed" area because it is blocked by the blade of the blind. We have seen this many times before and it freaks people out and they want to say it is from the sensor blooming or spilling over - it is not. Rick Link to post Share on other sites More sharing options...
CheshireCat Posted February 18, 2016 Share #313 Posted February 18, 2016 That is the shadow on the sensor from the edge of the blind with the bright light from the LoCA over falling the shadow like a penumbra. There is no bright light in the "dashed" area because it is blocked by the blade of the blind. We have seen this many times before and it freaks people out and they want to say it is from the sensor blooming or spilling over - it is not. Actually, in the "dashed" area there is bright light as much as to saturate the sensor. Not a problem, of course, because as I have always said in this thread, this is no sensor blooming/spillover. But is it UV/IR ? Link to post Share on other sites More sharing options...
Rick Posted February 18, 2016 Share #314 Posted February 18, 2016 Your dashes are my non-dashes. The area that is blue is in the area that is OOF with the POF behind. Notice, if you move to the right you see green behind the POF. Simple CA. It is just more pronounced in areas that are OOF because, part of what is OOF is the physical structure of the blinds. OOF areas cause shadows on the sensor around the edge of the blinds. These OOF areas are darker areas on the sensor that share ray traces from the sky to the sensor. Depending on the POF these areas will be purple/blue or green because of the way CA in the lens splits the light as it traces to the sensor from the lens. These are lens created and have nothing to due with the sensor. Stop the UV/IR question. it doesn't meet Occam's razor test. Rick Link to post Share on other sites More sharing options...
pgk Posted February 18, 2016 Share #315 Posted February 18, 2016 These are lens created and have nothing to due with the sensor. And thus the circle of life (well purple fringing life) starts again. I think that this thread has seen several rotations so far..... Link to post Share on other sites More sharing options...
willeica Posted February 18, 2016 Share #316 Posted February 18, 2016 And thus the circle of life (well purple fringing life) starts again. I think that this thread has seen several rotations so far..... I agree fully. This is an ongoing circular argument of little relevance to 'real photography'. If you have to choose subjects or blow up photos in order to produce this, then it is not a relevant issue. I have never come across this with film and I have seen this only rarely with digital. If this occurs it takes a couple of seconds to fix it in Lightroom or Photoshop. It is just a necessary and simple additional step arising from the nature of digital imaging. I have used many lens models from different manufacturers and the Leica Summilux 50 mm is the best lens I have ever used. For 'real photography', of course. William Link to post Share on other sites More sharing options...
CheshireCat Posted February 18, 2016 Share #317 Posted February 18, 2016 Well, some people like to understand why things happen. Others just don't care. That's fine, cause ignorance is bliss. Link to post Share on other sites More sharing options...
CheshireCat Posted February 18, 2016 Share #318 Posted February 18, 2016 It is just more pronounced in areas that are OOF because, part of what is OOF is the physical structure of the blinds. OOF areas cause shadows on the sensor around the edge of the blinds. These OOF areas are darker areas on the sensor that share ray traces from the sky to the sensor. Thanks, Rick but I am not sure I understand what you mean by "shadows on the sensor". Anyways, my new explanation is that the white sky is more out of focus than the white blind, hence the CA is higher there. Still I'll need to "raytrace" to be sure of this Link to post Share on other sites More sharing options...
Rick Posted February 18, 2016 Share #319 Posted February 18, 2016 CC - I'll PM you when I get a chance. Apparently, it makes no sense discussing it further in this thread about the subject. Because, the subject can't be understood with lens optics it must be something unexplainable that is happening in the sensor or that black box called processing. I'll vacate the thread now so others can talk about real photography. Rick Link to post Share on other sites More sharing options...
jaapv Posted February 18, 2016 Share #320 Posted February 18, 2016 I agree fully. This is an ongoing circular argument of little relevance to 'real photography'. If you have to choose subjects or blow up photos in order to produce this, then it is not a relevant issue. I have never come across this with film and I have seen this only rarely with digital. If this occurs it takes a couple of seconds to fix it in Lightroom or Photoshop. It is just a necessary and simple additional step arising from the nature of digital imaging. I have used many lens models from different manufacturers and the Leica Summilux 50 mm is the best lens I have ever used. For 'real photography', of course. William I have seen this on film but it appears to be more pronounced on sensors. Which to me proves that it is a multi-cause effect and that it makes little sense to try and pin it on one single aspect. Link to post Share on other sites More sharing options...
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