Olsen Posted February 20, 2010 Share #21 Posted February 20, 2010 Advertisement (gone after registration) Hi. Don't want to sound like a dumb ass, but whats C1 Duh! B Capture One. Link to post Share on other sites More sharing options...
Advertisement Posted February 20, 2010 Posted February 20, 2010 Hi Olsen, Take a look here Red Edge - Red Middle?. I'm sure you'll find what you were looking for!
Alnitak Posted February 20, 2010 Share #22 Posted February 20, 2010 This looks like a classic LoCA problem--Longitudinal Chromatic Aberration. I am guessing you used a really fast lens for this, nearly wide open? You will see LoCA with fast lens as bluish-cyan fringing behind the plane of focus, and reddish-magenta in front of the plane of focus. I have had this show up with fast glass on other platforms, such as the Canon 50/1.2L and 85/1.2L. A situation like you were shooting here--shooting into the light--greatly exacerbates the problem, as the bright specular highlights from the wet road combined with the dark background around those highlights will yield just this type of situation. In this case, the effect is also exacerbated by the specular highlights showing purple-magenta fringing in the plane of of focus. If you look closely at the image, you can actually see that the area in front of the plane of focus shows reddish highlights, then magenta-purple sharply focused, then bluish-cyan out of focus. Also note that you don't see this in the dark parts of the image, but only on the specular highlights. If you look really closely, you will likely see some of the LoCA in the other parts of the image at 100%. I will have to dig around in my archives and see if I can find some of my images taken with a variety of Canon cameras with fast glass that show just this effect. Jeff Link to post Share on other sites More sharing options...
TacTZilla Posted February 20, 2010 Author Share #23 Posted February 20, 2010 Capture One. Ah! Thanks. No. Don't have that software. Cheers B Link to post Share on other sites More sharing options...
Baptiste Posted February 20, 2010 Share #24 Posted February 20, 2010 Got that today, in a similar situation: wet ground, frontal sun. 50 Lux ASPH Link to post Share on other sites More sharing options...
Alnitak Posted February 21, 2010 Share #25 Posted February 21, 2010 OK, I found an image in my collection that demonstrates exactly what I was talking about. This was taken with my 40D and Canon 50mm f/1.2L, wide open. It's at the minimum focus distance, of just a few inches, so the total DOF is small. However, it was shot in conditions conducive to displaying the LoCA effect we are seeing here: I was shooting into strong light, at the lid of an Egyptian sarcophagus that was made of a very crystalline rock. The result was a lot of bright, backlit specular highlights with dark surroundings, and a very fast lens shot wide open. You can see the narrow plane of focus, and the exact same effect: Reddish in front of the plane of sharpest focus and bluish-cyan behind it. Here's a tighter crop of the zone of focus, and you can see the effect more clearly: So before anyone panics and blames Leica (AlanG): This is NOT a Leica problem, and this is NOT a sensor problem. It's a natural function of a very fast lens design shot under very specific conditions. Jeff Link to post Share on other sites More sharing options...
Alnitak Posted February 21, 2010 Share #26 Posted February 21, 2010 Oh, and it's not a software issue, either. This effect showed up several years ago with Aperture 1.0, and ACR 4.x and today I opened the image in Aperture 3.0 and ACR 5.6 and yes, it's still there. Jeff Link to post Share on other sites More sharing options...
diogenis Posted February 21, 2010 Share #27 Posted February 21, 2010 Advertisement (gone after registration) Is there a chance of this being something like the rainbow effect that happens when light passes through a prism under a specific angle? It all seems like a pattern to me with a very specific repeatability. All our photos are basically taken under same conditions: light, water(the prism) and at an angle... This photo shows these conditions. When I develop this using C1, the effect is almost removed. This one is developed with Apples developers. Also another suspicious element is the order in which colors appear... 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/112825-red-edge-red-middle/?do=findComment&comment=1233162'>More sharing options...
Alnitak Posted February 21, 2010 Share #28 Posted February 21, 2010 Is there a chance of this being something like the rainbow effect that happens when light passes through a prism under a specific angle?It all seems like a pattern to me with a very specific repeatability. All our photos are basically taken under same conditions: light, water(the prism) and at an angle... This photo shows these conditions. When I develop this using C1, the effect is almost removed. This one is developed with Apples developers. Also another suspicious element is the order in which colors appear... In essence, yes, it is LIKE a prismatic effect in that the glass is affecting the focal points of the different portions of the spectrum. Perhaps an explanation of Longitudinal Chromatic Aberration (LoCA) would help: Chromatic aberrations If you read that carefully, you can now see why this effect is an LoCA effect. Just as expected, the area in front of the plane of focus shows a bluish-cyan tint, as the blue portion of the spectrum is reaching focus slightly in front of the plane of best focus (which is for the green portion of the spectrum), and the red is slightly behind the plane of focus. As for why C1 would help eliminate it, that's because C1 does some pretty good reduction of color fringing by default, so it detects and eliminates those fringes. You can tweak things in ACR and get nearly the same effect, although its not as good at it as C1. Jeff Link to post Share on other sites More sharing options...
lct Posted February 21, 2010 Share #29 Posted February 21, 2010 Interesting, Jeff thanks. Viramati's pic above was shot at f/5.6 though. http://www.l-camera-forum.com/leica-forum/1237201-post15.html Link to post Share on other sites More sharing options...
Alnitak Posted February 21, 2010 Share #30 Posted February 21, 2010 Interesting, Jeff thanks.Viramati's pic above was shot at f/5.6 though. http://www.l-camera-forum.com/leica-forum/1237201-post15.html Yes, but stopping down won't totally eliminate this. It's inherent in the lens design. In the situation presented, the conditions are such that the effect will be visible even at f/5.6. The example I posted of the sarcophagus was shot at f/2.8, for example, and in a situation where the specular highlights are not as strong as the wet road examples, so the lens was stopped down nearly two stops and still showed the effect. What would be ideal would be to set up an example where we can run through a series of images at different apertures. Of course, I live in southern California, and it almost never rains here. Jeff Link to post Share on other sites More sharing options...
diogenis Posted February 22, 2010 Share #31 Posted February 22, 2010 Also, Viramattis pic is shot almost vertical. This shouldn't have happened like this. If it is light reflected and de synthesized, then angle should have been smaller. I will read that Loca thingy.. Link to post Share on other sites More sharing options...
Alnitak Posted February 22, 2010 Share #32 Posted February 22, 2010 Also, Viramattis pic is shot almost vertical. This shouldn't have happened like this. If it is light reflected and de synthesized, then angle should have been smaller. I will read that Loca thingy.. Why shouldn't it have happened? The angle of incidence will not eliminate the effect. It will alter the zone of focus in which it appears, but that's all. Jeff Link to post Share on other sites More sharing options...
diogenis Posted February 22, 2010 Share #33 Posted February 22, 2010 Well, I could say that if it was that thing, then -maybe not angle- but distance would actually amplify the LoCA. Also, his lens the 50lux I believe corrects CAs using special apo glass (not sure about that tho). Anyway, I haven't yet experienced this phenomenon like it is shown there. It is strange Link to post Share on other sites More sharing options...
Alnitak Posted February 22, 2010 Share #34 Posted February 22, 2010 Well, I could say that if it was that thing, then -maybe not angle- but distance would actually amplify the LoCA. Also, his lens the 50lux I believe corrects CAs using special apo glass (not sure about that tho).Anyway, I haven't yet experienced this phenomenon like it is shown there. It is strange It's a common misperception that APO lenses will not show chromatic aberration. The term "apochromatic" when used with lenses doesn't have a truly official status, but is generally used to indicate that all the spectrum is brought into focus at the same point. An apochromatic lens can still show LoCA, because the CA you are seeing is actually on either side of the plane of focus. All of that said, the 50mm 'Lux is not described as an apochromatic lens by Leica. The only lenses that have that designation are the 75mm APO-Summicron, 90mm APO-Summicron Aspherical, and the 134mm f/3.4 APO-Telyt. Jeff Link to post Share on other sites More sharing options...
diogenis Posted February 22, 2010 Share #35 Posted February 22, 2010 Yes I know, the 75mm is called "APO". I guess we can then test this with this lens then, but it is very difficult to redocument it... In any case, as an M8 shooter, I have never experienced this kind of CA, and I did shot a lot of torture pics against the light with dark objects, and all manifest like those lines in my pic, and not as surfaces. Link to post Share on other sites More sharing options...
Alnitak Posted February 22, 2010 Share #36 Posted February 22, 2010 Yes I know, the 75mm is called "APO". I guess we can then test this with this lens then, but it is very difficult to redocument it...In any case, as an M8 shooter, I have never experienced this kind of CA, and I did shot a lot of torture pics against the light with dark objects, and all manifest like those lines in my pic, and not as surfaces. I will bet you that if you set up a situation where an M9 shows this with a given lens, an M8 would show it with the same lens. Again, its a LENS problem, not a camera problem. Please refresh your memory by looking at my pictures with the exact same effect--taken with a Canon 40D and 50mm f/1.2L lens. Absolutely nothing in there related to the M9--but there is a fast lens, a strongly backlit high-contrast subject and the exact pattern of bluish-cyan highlights behind the plane of focus, and reddish-magenta in front of the plane of focus. It's classic LoCA in all of these cases: LENS not camera. Jeff Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2010 Share #37 Posted February 22, 2010 I doubt that. You can do it with any digital camera and with any lens. DMR Vario-Elmar 105-280: ( I missed focus, though ) 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/112825-red-edge-red-middle/?do=findComment&comment=1235026'>More sharing options...
lct Posted February 22, 2010 Share #38 Posted February 22, 2010 ...there is a fast lens... I'm learning a lot of things with your posts, thanks again, but how do you explain that a fast lens may show up that effect at f/5.6 and a slow one may not at f/5.6 as well? I'm no techie at all so forgive my question if it sounds stupid. Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 22, 2010 Share #39 Posted February 22, 2010 I'm learning a lot of things with your posts, thanks again, but how do you explain that a fast lens may show up that effect at f/5.6 and a slow one may not at f/5.6 as well? I'm no techie at all so forgive my question if it sounds stupid. It's an interaction of lens and sensor, as well as illumination levels. I don't know the exact reason (beyond over-exposure, that is) but all kinds of chromatic aberrations in digital behave this way. The Canon 85 1.2L--a spectacular lens--is well known for producing hideous aberrations under high-contrast light with Canon's digitals. Same goes for the not-so-fabulous 50 1.4 (a hideous Canon lens if ever there was one, IMO). On a 1ds2, with an adapter, the 80 R 1.4 Leica, btw, exhibits none of the artifacts the Canon 85 1.2L does (though the Leica isn't "as sharp" as the Canon wide open either). In the same way, some Zeiss wide designs exacerbate the M9 red issue and some of the same or similar focal length--but different design--don't. Remember this thread? It's one of dozens on the same topic...(scroll half-way down to see the issue)....but all digicams are susceptible to this. It has zero to do with Leica or Kodak (my Nikons do it too). http://www.l-camera-forum.com/leica-forum/leica-m8-forum/32960-sharpening-some-other-issues-m8.html Link to post Share on other sites More sharing options...
Alnitak Posted February 22, 2010 Share #40 Posted February 22, 2010 I doubt that. You can do it with any digital camera and with any lens. DMR Vario-Elmar 105-280: ( I missed focus, though ) Sorry, I should have been less authoritative. It's much more common in faster lenses, and it's easier to see in digital, but it's still a lens design issue, and not a camera issue--or even a digital issue. Take a look again at the link I posted, at the bottom of the page, and you will see it demonstrated on film. It's just that the nature of the digital sensors makes the issue more apparent. Jeff Link to post Share on other sites More sharing options...
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