lars_bergquist Posted July 29, 2009 Share #21 Posted July 29, 2009 Advertisement (gone after registration) Just look at the sensor - that greenish sheen is coating. It is not. It is a very thin absorption type IR filter that serves as the covering of the sensor. Leitz did originally believe that this would attenuate IR enough, and they were caught in a firestorm. If they had tested colour rendition on real subjects, and not simply on test targets in the lab, they would have seen the problem and probably not bothered about any internal IR filtering. But now it is there, as part of the sensor specifications I presume. With the M9, it will probably be gone. An over-sensor interference filter proved to be impracticable, exactly due to the extreme angles of the light behind the lenses of an M type camera. That is the reason why an absorption filter was chosen. But it could not be made very thick, as this would have led to a deterioration of the off-axis image. That does not mean that the sensor is uncoated. There is a coating, which is stated to be even harder than the glass itself (the hardness of various glasses varies considerably, by the way). But the green sheen is not an interference phenomenon, like the shimmering of coated lense surfaces, or that of the front-lens IR cutting filters. It is actual green glass! The old man from the Age of Kodak Lens Cleaning Tissue Link to post Share on other sites More sharing options...
Advertisement Posted July 29, 2009 Posted July 29, 2009 Hi lars_bergquist, Take a look here Cost of renewing sensor. I'm sure you'll find what you were looking for!
jaapv Posted July 29, 2009 Share #22 Posted July 29, 2009 Yes it is the anti-IR coating. IR filters are layers of coating. Link to post Share on other sites More sharing options...
tgray Posted July 29, 2009 Share #23 Posted July 29, 2009 I googled "Hardness of glass" and got a very varied response of mostly irrelevant links. The ones that were relevant seemed to rate glass as not particularly hard at all - the most relevant near the top of the list had this to say about glass: "Another clue to relative hardness is ease of scratching (both diamond and quartz scratch glass, but diamond scratches glass ". . . like a knife through butter")." note: "like a knife through butter". I know this is getting off topic, but... I would hope hope that diamond easily scratches glass, considering diamond is pretty much at the top of the hardness scale. To put things in perspective, glass is somewhere in the middle, between 5-6. Harder than steel, iron, titanium, somewhere on par or a little softer than quartz, softer than hardened steel, tungsten and diamond, amongst others. Of course, everything is pretty much softer than diamond. I know my phone has a glass face. I keep it in my pocket with whatever else and have for the last year and their are no visible scratches on the face of it. But then again, I don't walk around with a pocket full of diamonds... Though as stated, if the sensor glass has a coating on it, that's probably what would get scratched first. Link to post Share on other sites More sharing options...
plasticman Posted July 29, 2009 Share #24 Posted July 29, 2009 I know this is getting off topic, but... I would hope hope that diamond easily scratches glass, considering diamond is pretty much at the top of the hardness scale. To put things in perspective, glass is somewhere in the middle, between 5-6. Harder than steel, iron, titanium, somewhere on par or a little softer than quartz, softer than hardened steel, tungsten and diamond, amongst others. Of course, everything is pretty much softer than diamond. Fine - I really don't wanna get into some point-scoring debate about glass (about which I know virtually nothing more than the average joe), I just felt that the salient points were: - I felt the OP was issuing a legitimate warning about cleaning the sensor - the amount he paid is a lot of money, but I'm with Jaap that he actually got an ok deal when everything's factored in - my own experience is that I've noticed there's dirt on my M8 sensor after five or so(?) months of use (with practically the same lens on it for the first four months). I've never had to clean a sensor before, and even the RD1s has had more lenses on and off it for the last year-and-a-half without any visible dust anywhere (I also suspect the dirt is grease - to my totally inexperienced eye, I might add) - I get really tired by the 'you messed up and/or you must be lying' posts that almost always pop-up immediately anyone posts this sort of subject. In connection with this, the statement that it's virtually impossible to scratch a sensor because it's "one of the hardest substances in nature" was self-evidently wrong. That's how I took the way the thread unravelled. Hardly anything to get ignored for imho. But I think I'll survive. Link to post Share on other sites More sharing options...
tomasis7 Posted July 29, 2009 Share #25 Posted July 29, 2009 Hilarious stuff. Seriously. Anyway, just in case I'm not on the ignore list just yet, the point mjh is making is the opposite of what you were saying above. ignore him.. he puts like hundred guys on his ignore list.. including me lol and eventually you that's that attitude.. way strange lol.. however I didnt clean the sensor on rd1 yet.. only one time I had blow from my mouth to sensor (i know its stupid) but big particle came off then never did again .. but good to know that sensors can be sensitive.. I think it depends how much you press on cleaning with swab or so.. I rather use any blow tool.. Link to post Share on other sites More sharing options...
mjh Posted July 29, 2009 Share #26 Posted July 29, 2009 It is not. It is a very thin absorption type IR filter that serves as the covering of the sensor. Apparently everyone knows better than Kodak – I mean they are just manufacturing the sensor, so what do they know … Anyway, according to Kodak the sensor has a 0.5 mm thick coverglass (Kyocera B-7) doubling up as an IR absorption filter with a multilayer anti-reflective coating. Link to post Share on other sites More sharing options...
tgray Posted July 29, 2009 Share #27 Posted July 29, 2009 Advertisement (gone after registration) - I get really tired by the 'you messed up and/or you must be lying' posts that almost always pop-up immediately anyone posts this sort of subject. In connection with this, the statement that it's virtually impossible to scratch a sensor because it's "one of the hardest substances in nature" was self-evidently wrong. No problem with that - it's hard to argue with the fact that the poor guy's sensor got scratched. Assuming he didn't put it on the belt sander and did it while cleaning his sensor in a normal fashion, that really sucks. And one would hope that things like this shouldn't happen, certainly not when the replacement cost is so high. Link to post Share on other sites More sharing options...
jaapv Posted July 29, 2009 Share #28 Posted July 29, 2009 Apparently everyone knows better than Kodak – I mean they are just manufacturing the sensor, so what do they know … Anyway, according to Kodak the sensor has a 0.5 mm thick coverglass (Kyocera B-7) doubling up as an IR absorption filter with a multilayer anti-reflective coating. Don't be too hard on the old man from the age of dye gelatin filters, Michael Link to post Share on other sites More sharing options...
Shootist Posted July 29, 2009 Share #29 Posted July 29, 2009 Shootist - can you point me to the scientific papers that you base that opinion on please? I'm sure you wouldn't make such a sweeping statement (pretty much implying that the OP is lying) without at the very least having some factual backup. I quote your first reply to me again because I never said or implied the OP was lying. I did state that it would take a hard piece of grit and a lot of pressure to scratch glass. And I have been backed up on that from another poster. No where in my first reply did I say this didn't happen, that the price he quoted as paying wasn't true or that others shouldn't take care when cleaning there sensors. It seems, IIRC, you have had issues with some of my other posts. Why not just put me on your ignore list? That way you never have to read any of the posts I make to this forum. You'll probably be better off in the long run. I really have nothing to add and make very little sense most of the time. Link to post Share on other sites More sharing options...
tgray Posted July 29, 2009 Share #30 Posted July 29, 2009 To fully stir up the pot, Shootist, I think saying glass is hard is one thing, saying that is one of the hardest materials in nature is a bit much. Link to post Share on other sites More sharing options...
delander † Posted July 29, 2009 Share #31 Posted July 29, 2009 I think sand is harder than glass so that is a widely available material that could be the cause. Jeff Link to post Share on other sites More sharing options...
Shootist Posted July 29, 2009 Share #32 Posted July 29, 2009 I think sand is harder than glass so that is a widely available material that could be the cause. Jeff Well sand can be glass, silica sand. Link to post Share on other sites More sharing options...
mjh Posted July 29, 2009 Share #33 Posted July 29, 2009 I think sand is harder than glass so that is a widely available material that could be the cause. “Harder than window glass” to be precise, although “window glass” isn’t a terribly precise term. It is borosilicate glass (for example, Pyrex is borosilicate glass) the sensor’s coverglass is made of, by the way. Link to post Share on other sites More sharing options...
Jeff S Posted July 29, 2009 Share #34 Posted July 29, 2009 There was a post regarding sensor cleaning some months ago in which I recommended that the camera be sent to Leica for the job and I got lambasted for suggesting it on this forum. After 16 years of retail photography sales I saw too many people damaging their sensors by trying to do it themselves to the point that I wouldn't recommend any of the sensor cleaning methods we sold. Sensors are extremely delicate and should be cleaned by a factory trained technician. I'm sorry this happened to you but like it or not this is an example of trying to save some money gone awry. I use a Hurricane hand air blower on mine and if the spots get to be more than I want to deal with in PS it goes to the factory for cleaning where they assume liability. Your recommmendation may well have merit, but as I posted on another related thread, I find it amusing that "Leica's customer service uses nothing fancy but a homemade plastic spatula, dry optical cloths and isopropyl alcohol," according to LFI review article in issue 7/2007. The article explains how to do it yourself, after blowing dust first, and of course never setting the shutter on B as some have apparently done at great expense! Jeff Link to post Share on other sites More sharing options...
offshore Posted July 30, 2009 Share #35 Posted July 30, 2009 Your recommmendation may well have merit, but as I posted on another related thread, I find it amusing that "Leica's customer service uses nothing fancy but a homemade plastic spatula, dry optical cloths and isopropyl alcohol," according to LFI review article in issue 7/2007. The article explains how to do it yourself, after blowing dust first, and of course never setting the shutter on B as some have apparently done at great expense! Jeff This may be true Jeff but they also have liability when they do the sensor cleaning. They screw it up they replace it, you screw it up you replace it as this post illustrates. Link to post Share on other sites More sharing options...
Jeff S Posted July 30, 2009 Share #36 Posted July 30, 2009 This may be true Jeff but they also have liability when they do the sensor cleaning. They screw it up they replace it, you screw it up you replace it as this post illustrates. Yep, that's why I said recommendation to send away may well have merit. Otherwise, I just find it amusing, since I would have expected the author to describe Leica's practices as employing some ultra technical procedure, using sophisticated equipment and precise and delicate care...not a homemade plastic spatula. And, suggesting how users might do something similar. Jeff Link to post Share on other sites More sharing options...
AlanG Posted July 30, 2009 Share #37 Posted July 30, 2009 Are you absolutely certain it was scratched? The reason I asked is that I thought I had a scratch on one of my DSLR cameras for several years. (It didn't often show up too badly so I accepted it.) And my normal wet cleaning didn't remove it. As the camera became older and I rarely used it, I decided to try to clean it very vigorously...despite any risk of producing more scratches. I used a PEC pad on a small rubber spatula with Eclipse and rubbed it pretty hard quite a number of times. The "scratch" went away. Link to post Share on other sites More sharing options...
hoppyman Posted July 30, 2009 Share #38 Posted July 30, 2009 A friend of mine had to clean his M8 sensor when ink from trying to code lenses got onto it. He initially used a number of swabs delicately in the prescribed manner. He ended up having to scrub roughly and repeatedly to remove the residue. There is no visible damge nor detectable problem with the images now. I think those sensor cover glasses are tough. Of course we should always take care and use the proper technique. Assuming that the original poster had a physical scratch It does seem as though something hard like a particle of sand has been involved. Of course no camera sensor is immune to damage. Must have been horrible to find. I hope the repaired camera gives many years of great service. Link to post Share on other sites More sharing options...
lars_bergquist Posted July 30, 2009 Share #39 Posted July 30, 2009 Yes it is the anti-IR coating. IR filters are layers of coating. No. There are two different kinds of IR cutting filters, interference and absorption. Interference filters, like the screw on Leica and B+W filters, reflect IR forward. They also reflect some deep red, which is the cause of the red sheen you see. Absorption filters are just that: They stop IR just like a yellow filter stops blue, its complementary colour. So just as the yellow filter looks yellow, the IR filter, a green filter, looks green, because it IS green in the mass. If there had been an interference filter over the sensor, it would have had the same 'red eye of Mordor' look as the lens filters have. Go read up on filter technology. If you won't believe me, ask Leica. The old man from the Age of the Yellow Filter Link to post Share on other sites More sharing options...
lars_bergquist Posted July 30, 2009 Share #40 Posted July 30, 2009 Apparently everyone knows better than Kodak – I mean they are just manufacturing the sensor, so what do they know … Anyway, according to Kodak the sensor has a 0.5 mm thick coverglass (Kyocera B-7) doubling up as an IR absorption filter with a multilayer anti-reflective coating. Yes, Virginia. The green cover glass is thin, so it doesn't absorb very much IR. But it is the glass that does the absoption. The multilayer coating is for reflex suppression, not for IR protection. If multi-layer coating as such protected against IR, why would we have this IR issue? Every damn lens would be IR safe. The coatings on IR cutting filters is specially computed to act on wavelengths above some 700-750 nanometers. It is not the same as just any multi-coating. If you parse the Kodak statement, you will find that it does not say that the coating does it, which implies that it is the Kyocera B-7 glass that does it. But they should have been less frugal with their commas: "... a 0.5 mm thick coverglass (Kyocera B-7) doubling up as an IR absorption filter, with a multilayer anti-reflective coating." Again, if you won't believe me, ask Leica: "Dear Sir, is it the absorptive glass OR the coating that attenuates IR?" They won't lie to you. The old man from the Age of the Yellow Filter By the way, I never ever used gelatin filters, not even cemented ones. There is a limit ... Link to post Share on other sites More sharing options...
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