otto.f Posted June 8, 2011 Share #101 Posted June 8, 2011 (edited) Advertisement (gone after registration) Olsen: This thread was started out of curiosity, not out of need to give expression to disappointments, I sincerely hope we can keep it this way Edited June 8, 2011 by otto.f Quote Link to post Share on other sites More sharing options...
Advertisement Posted June 8, 2011 Posted June 8, 2011 Hi otto.f, Take a look here Towards an explanation of the Italian Flag Phenomenon. I'm sure you'll find what you were looking for!
Lindolfi Posted June 8, 2011 Author Share #102 Posted June 8, 2011 Pop, part of the problem with that idea is that the resulting image comes from processing of neighbouring colour sites and so you would not get the contribution of individual colour sites to the RAW image. Now there are interference filters, which produce a very narrow band of wavelength (at a very low intensity), so with good focussing it should be possible to create a light edge. But since the spill over is in the dark bits between the colour sensitive sites, you would not see too much happening at that edge in terms of the principle that I proposed. Quote Link to post Share on other sites More sharing options...
pop Posted June 8, 2011 Share #103 Posted June 8, 2011 But since the spill over is in the dark bits between the colour sensitive sites, you would not see too much happening at that edge in terms of the principle that I proposed. That depends a bit on the exact mechanism or mechanisms leading to the IFP. I know that I might be barking up the wrong tree. The arrangement with the (close to) monochrome light would detect if there was any spilling of - say - red light into blue or green pits. If the edge was spread over several pits or even pixels, the width of the spread might also be useful for formulating a model of the cause. What is the quality of the light emitted by laser pointers of similar solid state "lasers"? Quote Link to post Share on other sites More sharing options...
Lindolfi Posted June 8, 2011 Author Share #104 Posted June 8, 2011 I've already thought of lasers (nicely monochromatic), but they need to be focussed using a lens, creating spread by itself. Now you could use a combination of a slit and a laser to reduce the spread. Quote Link to post Share on other sites More sharing options...
Olsen Posted June 8, 2011 Share #105 Posted June 8, 2011 Olsen:This thread was started out of curiosity, not out of need to give expression to disappointments, I sincerely hope we can keep it this way I am just expecting a streight answer from somebody who might know: Can the Italian Flag Issue be fixed with a software up date? Quote Link to post Share on other sites More sharing options...
Lindolfi Posted June 8, 2011 Author Share #106 Posted June 8, 2011 (edited) Olsen, given what is possible now with the present firmware (a wide variety of corrections), I expect it can be done. If not, you can do it in postprocessing in great detail: just set up your zero images (using a white opaque lens cover) at verious apertures for all your lenses and correct to a perfect even colour transfer. Edited June 8, 2011 by Lindolfi Quote Link to post Share on other sites More sharing options...
Olsen Posted June 8, 2011 Share #107 Posted June 8, 2011 Advertisement (gone after registration) Olsen, given what is possible now with the present firmware (a wide variety of corrections), I expect it can be done. If not, you can do it in postprocessing in great detail: just set up your zero images (using a white opaque lens cover) at verious apertures for all your lenses and correct to a perfect even colour transfer. Thanks. Quote Link to post Share on other sites More sharing options...
jaapv Posted June 8, 2011 Share #108 Posted June 8, 2011 I am just expecting a streight answer from somebody who might know: Can the Italian Flag Issue be fixed with a software up date?Yes - shoot a second shot through a piece of white paper, make an LCC profile in C1 - 5 seconds and only once- and the correction is one mouseclick and 100% Quote Link to post Share on other sites More sharing options...
Washington Posted June 9, 2011 Share #109 Posted June 9, 2011 Honestly, so much of this is over my head…. but, I was wondering about Leica lenses. I DO NOT KNOW, but I assume the lenses have to be produced to compromise betwixt film and sensors. Am I close to being right? Perhaps it would take a total lens redesign to optimize a wide-angle lens just for the M-9??? Just a thought based on no knowledge what-so-ever. Cheers. Quote Link to post Share on other sites More sharing options...
otto.f Posted June 9, 2011 Share #110 Posted June 9, 2011 Honestly, so much of this is over my head…. but, I was wondering about Leica lenses.I DO NOT KNOW, but I assume the lenses have to be produced to compromise betwixt film and sensors. Am I close to being right? Perhaps it would take a total lens redesign to optimize a wide-angle lens just for the M-9??? Just a thought based on no knowledge what-so-ever. Cheers. No that's not possible alas, you can't build wide-angles that do not have a small angle of incident on the sensor Quote Link to post Share on other sites More sharing options...
Washington Posted June 9, 2011 Share #111 Posted June 9, 2011 If you say so I can not disagree because I just don’t know. But still: why do some of my 21’s have less red-edge than others???? Quote Link to post Share on other sites More sharing options...
adan Posted June 9, 2011 Share #112 Posted June 9, 2011 (edited) No that's not possible alas, you can't build wide-angles that do not have a small angle of incident on the sensor Well, you can, but they cease to be as compact as Leica M wideangles. SLR superwides and wides are built without a shallow angle of incidence, by virtue of having to sit so far away from the sensor or film to allow room for the SLR mirror (retrofocus design). Google up an image of a Nikon or Leica R 15mm lens, to compare to, say, the Cosina 15mm. Or for real laughs, compare a Nikon 14-24 - http://www.kenrockwell.com/zeiss/slr/images/21mm/compared/D3S_8771-1500.jpg - to anything made to fit Leica M's in that range. (keep in mind that the SLR lenses pictured, in addition to their actual size, also sit at the front of a mirror box when in use. So their "operational size" is bigger yet by 1/2" or so. @ Washington - Why do some 21's produce more red-edge (or, in fact many other differences)? Because '21mm" is just a focal length, not a specific optical design. There are big differences in the optical layout even among M-mount lenses. There are as many ways to design a 21mm as there are ways to build yachts that conform to the "America's Cup" rule. > The old symmetrical, non-retrofocus designs of the Super-Angulons and original Biogon of the 1960's > The mildly retrofocus and larger designs of Leica since 1980, to push the lens away from the film for metering reasons. > The mildly retrofocus but compact Zeiss ZM f/4.5 and c/v f/4 > The stronger retrofocus design of the "new" Zeiss Biogon ZM f/2.8 > The WATE and the 21 Summilux (designed, I'm sure, with digital imaging in mind as well as film) Go here: Biogon T* 2,8/21 ZM and download the separate "product flyers" (bottom right corner) for the two Zeiss ZM 21s. The optical x-sections are on the second page for each. Same focal length, same company, same era, and yet very different in the size and shape of the glass and light path (the f/2.8 is nearly twice as long as the f/4.5) Edited June 9, 2011 by adan 2 Quote Link to post Share on other sites More sharing options...
Ario Arioldi Posted June 9, 2011 Share #113 Posted June 9, 2011 I'm not sure if this has been noticed already but the Italian Flag Phenomenon affects also the Phase One Digital Backs and some detail and explantion can be found in the Phase One Knowledge Base. This is one example: Phase One camera system - Raw conversion software - Photo management 2 Quote Link to post Share on other sites More sharing options...
Lindolfi Posted June 9, 2011 Author Share #114 Posted June 9, 2011 (edited) No that's not possible alas, you can't build wide-angles that do not have a small angle of incident on the sensor The focal length can be much shorter than the distance between rear element and film/sensor plane: compare for instance the sigma 12mm lens on a D3 camera, which has a focal flange distance of 46.5 mm. This in contrast to the focal flange distance of the Leica M, wich is 29.5 mm. The distance from the back element of the Heliar 12/5.6 to the film plane is about 14 mm. When you look at the ray diagrams in the Leica lens compendium by Puts (2001) in which drawing scale is given and you intersect the rays on the sensor back into the lens and measure the distance between sensor and this intersection point, it is longer than the focal length in for instance the Elmarit 2.8/21. The reverse is true for telyt lenses in which the focal length is much longer than the distance between the back nodal point and the sensor plane. So there is a room in the design of lenses to change the angle of incidence at a given focal length. That explains the difference in Italian Flag Phenomenon between lenses of the same focal length. PS: while writing this, Adan wrote an interesting post, which is in line with this statement. Edited June 9, 2011 by Lindolfi 1 Quote Link to post Share on other sites More sharing options...
Lindolfi Posted June 9, 2011 Author Share #115 Posted June 9, 2011 I'm not sure if this has been noticed already but the Italian Flag Phenomenon affects also the Phase One Digital Backs and some detail and explantion can be found in the Phase One Knowledge Base.This is one example: Phase One camera system - Raw conversion software - Photo management Nice to see the phenomenon and white sheet correction in Phase One, but unfortunately no explanation is given of the cause the phenomenon, only of the way how to correct for it. Quote Link to post Share on other sites More sharing options...
Washington Posted June 9, 2011 Share #116 Posted June 9, 2011 See Guys, I don’t know squat about design….. all I know is some lenses of the same focal length work better than others. I will never design a lens or know the whys…. but, this was only my observation. I just take photos. And, I like my M-9 no matter what. If my photo is a ‘’keeper’’ I just fix it. Quote Link to post Share on other sites More sharing options...
otto.f Posted June 9, 2011 Share #117 Posted June 9, 2011 If you say so I can not disagree because I just don’t know.But still: why do some of my 21’s have less red-edge than others???? As I said earlier, it depends mainly on how short the distance is between the rear lens of your type of 21 and the sensorplane, and on the widest aperture of a lens Quote Link to post Share on other sites More sharing options...
Ario Arioldi Posted June 9, 2011 Share #118 Posted June 9, 2011 Nice to see the phenomenon and white sheet correction in Phase One, but unfortunately no explanation is given of the cause the phenomenon, only of the way how to correct for it. No true explanation, but interesting to see that also in PO is a corner-to-corner (not side to side) color shift, that is influenced by the lens geometry and by the angle of incidence of the light, that is specific for each individual sensor. "Lens cast is a result of the CCD being exposed to light from a very sharp angle and will typically occur as a green cast in one corner of the image, stretching into a magenta cast in the opposite corner. If you tilt the camera, zoom or in any other way change the way the light will enter the lens, you need to create a new calibration file. Since CCDs are unique and the camera calibration files that R&D develops for each sensor is unique the LCC files can only be used with that specific RAW files." Quote Link to post Share on other sites More sharing options...
giordano Posted June 9, 2011 Share #119 Posted June 9, 2011 I am just expecting a streight answer from somebody who might know: Can the Italian Flag Issue be fixed with a software up date? If the IFP is caused or influenced by camera-to-camera variation in the position of the microlens array in relation to the sensor, it cannot be fixed with a firmware update that necessarily applies the same correction to every camera. But it could in principle be tackled by giving each camera custom firmware tailored to its particular sensor. In practice this might be done by splitting the firmware code in two: one part with the IF correction data and the other with everything else. The first part would only be updated if the sensor was changed; the second would be field-updated as normal. Whether the M9 hardware allows this is another question. 1 Quote Link to post Share on other sites More sharing options...
otto.f Posted June 9, 2011 Share #120 Posted June 9, 2011 Nice to see the phenomenon and white sheet correction in Phase One, but unfortunately no explanation is given of the cause the phenomenon, only of the way how to correct for it. But that could mean that IFP has nothing to do with micro-lenses and/or their chromatic aberration. As described by PhaseOne, it evokes the thought of a sort of prisma effect in the glass covering the sensor Quote Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.