Jeff
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 p.1 #5 · When did the 1Ds get the 'new' sensor? | |
So, to recap from the last thread, my 1Ds (purchased new 3/03) exhibited banding in the 1/4-tones in properly exposed images; that is, the 'macro-scale' banding showed up in darker tones, like navy suits. For example (and this is what I sent to Canon):
The sensor was replaced by Canon, under warranty, at about 11 months and 2 weeks of age. It did take a bit of going around with them to finally show them that it wasn't an underexposed image that I was over-tweaking the gamma, but I did convince them. Secondarily, if you do have an underexposed image, or if you severely open up the shadows, from my experience any 1Ds will exhibit similar behavior, and it's mostly (or all?) in the red channel. This does not mean that there is anything wrong with the camera, just that there is something wrong with the exposure, and you shouldn't be pushing it that far. It's when this behavior manifests itself in the darker tones of a properly-exposed image that you have a problem.
In summary, I'm nearly certain that Canon never owned up to any large-scale problem with the 1Ds production line (nor do I think they should have, from what little I've seen of the 'issue'), and am equally 'certain' that there is no way to identify any serial number run or timeline to indicate that a given camera should/should not have the problem. I believe that it was more of a random occurrence (production-wise), and that other than testing a given body, there's no other way to predict whether that body will or will not exhibit the behavior, (other than the fact that it is statistically unlikely). What Canon knows of this issue is anybody's guess. RD Grier's 5D chroma noise issue (above) is more endemic to the Canon CMOS sensor, is easily rectified in post, and is most certainly not what is illustrated in the example image above, even though it is admittedly 'color noise in the shadows'. I've only seen this 'macro-scale banding' from 1Ds MkI models, though other cameras may exhibit such garbage data when the image is pushed too far.
As far as knowing if the sensor was replaced, I have no idea whether even Canon keeps such records long-term, and absent the paperwork showing that the sensor assembly was indeed replaced, I doubt there's any way to know by examining the camera. Even so, does it really matter? If the sensor doesn't exhibit the phenomenon, I don't think I'd care one way or the other if the sensor was 'original' or not. As long as it worked properly.
Hope that helps.
Jeff
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