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Thread: Is this M9 sensor broken--or just blooming?

  1. #1
    Senior Member 4season's Avatar
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    Is this M9 sensor broken--or just blooming?

    Hi all,
    A few weeks ago, I sold my M9 to a fellow forum member. Today, he contacted me concerned that the sensor may be failing. I looked at the sample photos he provided (posted below with his permission) and thought it was simply an artifact caused by an overloaded CCD, but he's still bothered because the green blotches appear in roughly the same area in all of the photos. We could use some some unbiased opinions here! I've renamed and scaled the photos to 1024 px but made no other changes.

    Buyer also noted that the problems seemed to appear most often slow shutter speeds, but I felt it was simply a coincidence.





    All photos have similarly blown highlights:

    So what do you folks think: Hardware problem, improper technique or..?

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    Re: Is this M9 sensor broken--or just blooming?

    Just a quick note from the buyer here: the green cast is hard to see in the third and fourth pic above, but it is there, in the exact same spot as the first two, in the extreme left upper edge of the pics, best seen on full resolution, which is not possible here. One more point, these are taken on different days, under very different lighting conditions, with the camera in AE mode, all with iso 160, with different lenses (zm 50 and elmar 50) So the question is, to M9 owners, has anyone seen this occur in your pictures.

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    Senior Member dude163's Avatar
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    Re: Is this M9 sensor broken--or just blooming?

    My Camera ( M8 ) did this if I shot too many shots in a row, almost like the buffer couldnt keep all the data . I bought a new memory card and it stopped .

    Did the buyer get your old card with the camera? or did theyuse their own?

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    Re: Is this M9 sensor broken--or just blooming?

    I have no idea what I am looking at here.

    One person says 'green blotches in roughly the same spot', the other says 'green cast in exactly the same spot'. Can you do a pointy arrow to the green blotch/cast?

    All I do see in the upper left of each picture is extreme over exposure blowing out the highlights. First things first, is the monitor calibrated, have you removed any overall colour cast from the image (especially if using Auto WB in camera)? I would suggest using the camera in manual mode until you get used to the auto metering, and don't just rely on the LCD thumbnail for an indication of an good exposure, look at the histogram. Good luck.

    Steve

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    Senior Member Ario Arioldi's Avatar
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    Re: Is this M9 sensor broken--or just blooming?

    In my view they are just heavily overexposed.
    Ario
    www.arioarioldi.net
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    Re: Is this M9 sensor broken--or just blooming?

    Overexposed blown highlights / clipping and some lens flare.

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    Re: Is this M9 sensor broken--or just blooming?

    Quote Originally Posted by DDudenbostel View Post
    Overexposed blown highlights / clipping and some lens flare.
    +1

    I think there's something wrong with those pictures, the unnatural green on the top of each image seems really strange, regardless of the obvious overexposure, have you tried also switching SD cards?

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    Workshop Member glenerrolrd's Avatar
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    Re: Is this M9 sensor broken--or just blooming?

    You should do some tests with even lighting and proper exposure ..just to eliminate unnecessary variables in your testing protocol. I have taken 10 s of thousands of captures with 3 different M9 s and you will get strange renderings every so often when shooting into the light ..but this is like one in every few hundred at most.

    Keep in mind that the camera needs the 6 bit information to correct for color shading on the edges . I would take a few shots filing the frame with a grey card . Its not perfect with all lenses but in normal photographs its not bothersome.

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    Workshop Member glenerrolrd's Avatar
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    Re: Is this M9 sensor broken--or just blooming?

    Forgot to mention that you always should start any testing with a fresh battery and a reformatted card . Just eliminate the possibility that you are getting incomplete writes to the card .

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    Re: Is this M9 sensor broken--or just blooming?

    I took a look at the histogram of each image in photoshop. Every image has excessive clipping in the high values and flare causing the shadows to be elevated. The shooter was exposing for the shadows and allowing the high values to fall where they will in a very high contrast situation. The contrast range exceeded the dynamic range of the camera. The odd coloration is due to the major clipping in the green channel. The red and blue are clipping too but the green more so. The sensor / processing engine just can't handle that extreme level of information.

    Not even Leica or Zeiss glass is immune to flare. Matter of fact I sold my late Summicron 50 in favor of a ZM Planar for that reason. You can see the flare / haze in the shadows and can certainly see it in the histogram especially the one with the trailer.

    Things that will help improve this but not cure it. I see you shooting in sRGB. The gamut is much reduced in sRGB vs the much wider gamut of Adobe RGB. Use Adobe RGB. Are you shooting JPG or raw. Raw gives many more options to recover the data in shadows and highlights. Always convert your raw to 16bit color Adobe RGB and work the files in 16 bit as much as possible then convert to 8 bit for processing. Shooting jpg throws a lot of the data away and and leaves you to the mercy of some engineer that designed the file processing / look of that camera. If you're using a filter that adds two more surfaces for flare to happen. I almost never use a filter even if it's the top of the line and multi coated. Bracket your exposures and pay attention to your histogram. it doesn't matter what your meter says it's all about what the histogram says. The histogram is the absolute truth about your image. Finally calibrate / profile your monitor. Unless you do that you're just guessing and generally guessing wrong.

    My remarks come from 45 years of professional experience. I've seen this dozens of times with film and digital alike.

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    Re: Is this M9 sensor broken--or just blooming?

    I think it was mentioned to shoot an evenly lit neutral card at various exposures from almost black to almost white and see if they appear. Try different lenses and repeat.

    If there's some problem with the sensor it would be on the bottom edge. Put the camera in the sensor cleaning mode without a lens and examine the sensor under strong light to see if there is any physical defect. I still believe it's due to flare and overexposure. It may even be due to some internal flare in the body itself coupled with the other two problems. I don't believe it has anything to do with a card or battery.

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