Sensor Corrosion Analysis and Fix [Merged]

[guyplatt]

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On 2/17/2022 at 10:27 PM, dllewellyn said:

I have repaired sensor corrosion on M9, M9P, M-E, Monocrom and S2 cameras.  My guess is around 100,000 cameras affected because when you take off the bottom cover, you can see a handwritten serial number on the chassis, and I have seen numbers as high as 86,000.

Hi, I know this is an old thread, but are you still doing repairs? My M9 shoots half an image :(

[dllewellyn]

1/2 black sensor means 1/2 the sensor is dead.  That isn't a sensor corrosion issue.  The M9 series sensors are two APS sensors that have been stitched together.  One side can fail and the other still work.  You need a new sensor which means finding a donor camera around - which is pretty hard these days.

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[jaapv]

As a matter of fact it is not. It is a single sensor that is read out in two halves (for. speed)  Probably the sensor did not fail, but the motherboard. Nothing more than a technicality, though, as the camera is irreparable in any case. Sensor and motherboard are one unit. If you find a donor camera it is more logical to use the dead one as a donor and fix the one you found.

[dllewellyn]

Think you are wrong about that Jaap.  Here is some information from a guy I know who used to design image sensors and still works in the industry in management now.

First off, all 35mm FF sensors are stitched. No way around it. The stepper reticles FOV used in fabs are not large enough to image a FF sensor in one shot. APS sensors can be made in one shot but they hit the limits on reticle aperture; in fact most APS sensors designs are reticle limited. Cost is a MAJOR reason why the digital camera industry way back in the day focused on APS sensors since they could build them on one reticle field.

 

Most fabs have reticle limits of ~30x30mm. I think TSMCs stepper reticles are ~26x~28. To step a 35mm sensor you need minimum of 2 shots; the 24mm active area fits on the 28-30mm field height, and you do 2 shots, L/R halves, so there is a stitch line down the middle. Medium format sensors are minimum of 4 shots.

 

Fabs HATE stitching since it screws up the ‘flow’ of steps/wafer/machine etc. The stitched wafers are in the stepper longer than the other wafers in the line since they have to shot multiple shots, and the wafers behind them only need one shot etc. Most fabs will stack up the stitched work and run it al lat the same time, like maybe once per month.

 

The stitch line has to be processed out or it will be obvious. It is impossible not to have some type of visible disturbance at the stitch boundary. If anyone ever tells you that they don’t have stitch boundary processing they are BS’ing. The reason is, if you think about it, the stepper lens is not perfect, and at the boundary, you are imaging the reticle with the left side of the lens on one shot and the right side on the other. That fact convolved with the accuracy of positioning the reticle at the boundary creates a very small anomaly that ends up disturbing how the pixel collects and processes the photon signal. These anomalies gets more difficult to deal with as pixels shrink. The 4um pixels (45mp cameras) are much harder to make than a 6-9um (12-24mp). IMHO you will never see a ~150Mp 35mm camera for this reason. Yields on this device would cause the camera to price at $10-20K and nobody could afford it. Could it be built, yes, but the stitching artifacts would be larger and more difficult to deal with, probably causing lower ISO range too (super high digital gains in the ISP would make stitch management artifacts very difficult. Besides, there is a limit to ‘practical’ MP in DSLRs. At some point users wont pay, and the file sizes get stupid. They are better off investing in auto-focus, frame rate, or some other useful photographic aspects, not just pixel count. IMHO 35mm DSLRs will stop the MP wars at the 60-90mp tier. 60mp is a 3.8um pixel; 96mp is a 3um pixel (8x x 12k). ISO and dynamic range on a 3um pixel gets tough too for Pro performance.

 

From a stitch management perspective every camera has to be uniquely calibrated to remove the stitch boundary anomalies. Both the dark offset and responsivity has to be processed to match both halves at the boundary. Offsets are different since the column amplifiers are also on both sides of the stitch and this can affect how the transistors are made, etc. These are very small differences, 1-2DN, at most but make huge problems at high ISO when the digital gains are high. (A “DN” (digital number) is the RAW digital number coming out the A/D converter in every column; for a 14 bit ADC, the range of DN’s is 0-16383). Responsivity is a linear gain adjustment to match the halves. Typically they would uniformly light up the sensor to ~75% full range then measure the DN values after dark subtract. Then compute a correction gain. This gain may also be done at various ISO ranges to accommodate the sensors non-linearity across the full range. These offset and gain adjustments can also be done differently from the top compared to the bottom of the sensor, due to gradients affecting offset/gain across that distance (second order affects from the stepper, for example stepper lens distortions between the left/right halves)

 

Secondarily…..if you use a stitched sensor in the NIR range, it was not stitch calibrated in that wavelength regime. This immediately will cause issues, albeit small, since the NIR light images at a different depth in the silicon, and the cross-talk is higher across the stitch boundary. I have no experience in this regime, but my opinion here is the NIR light is going to cause problems, and that may be noticeable in final images. The ‘test’ for this is to setup a experiment that has a wide band source form 400-1000nm (e.g. tungsten light source). Then capture flat-field images with a green notch filter that images, maybe, wavelengths from 500-550 and another filter that images 850-900. Use the same exposure and ISO for both shots, etc. then process the RAW files and boost the levels. I would bet you will see stitch issues in the NIR shot that are not in the green shot. Might need extreme levels adjust (beyond what typically would be used to process a normal image)

[dllewellyn]

Also, I once made the mistake of breaking one of the gold bonding wires when removing a corroded (oxidized) ICF/Coverglass.  The result was a 1/2 black image.

About a year ago, I noticed an M9 being sold on eBay by a place in southern NJ. I know the town is where one of my competitors is located so I knew it was being sold by them.  In the eBay description, they said camera takes a 1/2 black picture and sensor might be damaged.  I wrote them an email and told there was no 'might' - the sensor was damaged and got damaged when they broke one of the wires.  Then they told me the bonding wire corroded on its own.  Again, I told them 'nope.  The bonding wires are 99.99% pure gold and that doesn't corrode'.  Then they said the corroded glass broke the bonding wire and wanted to know why I was being a pain.  I explained that I knew exactly what happened, and they were being misleading in their description.  The camera ended up selling for around $850 to some poor soul and then got resold as various people figured out that the sensor was damaged.

I have also seen M9 sensors fail that way on their own.  In every case I have seen, it has been a sensor failure.  So I always ask someone who wants their camera repaired if the camera is taking a full image and everything else is working OK.

[lumini]

My M9, which I have had since new in 2010, has died.  I had not used it for about 9 months as I have an SL2-S but wanted it this week as a lighter option.  The results accord with the descriptions in this and other threads of motherboard failure.  I am in mourning.

Geoff

[Anthony Miller]

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I saw a rather concerning post on a Leica Facebook group for the M9 showing what looks like sensor corrosion on an ID15 sensor. My understanding (from Leica NJ) is that the ID15 and 16 are "non-corroding" and I assume because the improved/correct cover glass was used on these. I think the ID11 is still subject to corrosion.

Has anyone else experienced a similar issue with an ID15 or 16 sensor?

 

[swatch]

Don’t know how Kolar being able to source new CCD  sensor ( in addition to service of replace cover glass Kolar has been doing for some years ) to replace that of M9.  Please find their offer per below link :

 

https://kolarivision.com/product/kolari-sensor-replacement-service-for-the-leica-m9-camera/?fbclid=IwAR2I7vJMOQI1CxMKhtxvzoIxl8hHxaWyUSZbPvMHFrynONjC_r9AGcMV9l4_aem_AcE_rKtfoY3QZ2tKl13rphqTHwxbINpoTsB3QEqKiErKxAUZ9omMAnjKlcw3jpas6fg&mibextid=Zxz2cZ

[TomB_tx]

I don't believe Leica ever did sensor replacements on the M9, as they only bought complete circuit-board / sensor assemblies from their supplier, so their expertise was not in such component replacement.

[dllewellyn]

The M9 camera sensor is mounted in a PCB where the sensor is soldered onto the PCB.  When Leica replaced the M9 sensors, what they meant was that they replaced the entire sensor PCB - not just the sensor itself.

[swatch]

1 hour ago, dllewellyn said:

The M9 camera sensor is mounted in a PCB where the sensor is soldered onto the PCB.  When Leica replaced the M9 sensors, what they meant was that they replaced the entire sensor PCB - not just the sensor itself.

Guess M9 owners would prefer Leica to continue to replace the CCD module which is still available from supplier since Kolar seems able to source it.

M9 is the first full frame digital rangefinder camera and it is classic. 

[dllewellyn]

Not correct.  Kodak originally made the M9 sensor.  The division was spun off to TrueSense which was later acquired by OnSemi.  OnSemi stopped making all CCD sensors a couple years ago.  Kolari is not sourcing the sensor other than buying an M9 and removing the sensor PCB assembly.  Not sure where you are getting that Kolari is sourcing sensors.  Happy to be proved wrong, but I highly doubt it.

[swatch]

On 7/4/2023 at 8:50 AM, dllewellyn said:

Not correct.  Kodak originally made the M9 sensor.  The division was spun off to TrueSense which was later acquired by OnSemi.  OnSemi stopped making all CCD sensors a couple years ago.  Kolari is not sourcing the sensor other than buying an M9 and removing the sensor PCB assembly.  Not sure where you are getting that Kolari is sourcing sensors.  Happy to be proved wrong, but I highly doubt it.

Kolari’s web site state they are offering below services:

1) replace cover glass

2) replace sensor module 

How Kolari can do the above number 2 is unknown.  Anyway it is good to have third party offering options to M9 owners.

[dobritch]

I’m rather late to this party… but that said Leica Uk have just confirmed a corroded sensor in my M9. 
They obviously suggest it’s not a fault/defect.
 

“I can confirm the sensor on your camera is affected by corrosion. We unfortunately can no longer repair or replace the sensor of the Leica M9.

Please allow me to explain the sensor topic in more detail. In some cases, when using the Leica M9, images may show effects caused by surface corrosion of the sensor cover glass. The sensors are equipped with a specially coated IR filter cover glass to ensure optimum imaging performance. Should this coating layer be damaged, corrosion effects that change the structure of the filter surface can begin to appear after several years. The sensor problem described may not necessarily occur throughout the entire life cycle of many cameras and is therefore not considered a serial flaw/manufacturing defect.”

My question which may seem naive, is did anyone successfully make an insurance claim, against this problem?

Any 2cents welcome. I’m somewhat devastated.

 

[dllewellyn]

Of course it is a defect  I have been working on cameras for over 25 years, and I have *never* seen coated glass inside a camera go bad.  I was the first to document and publish an article about their sensor 'corrosion'  (actually oxidization of the glass).  If the glass were correctly coated, which seals the glass, then the ICF / coverglass would not oxidize.

Leica won't admit they made a mistake.  For that matter, I find it odd that many Leica customers refuse to believe the Leica (Kodak/TrueSense/OnSemi) could make a mistake.  Unfortunately, the sensor supplier to Leica stopped making all CCD sensors.  The M9 series is pretty old, and Leica isn't going to find another manufacturer to make the sensors.  At this point, if you have an oxidized sensor, you can: leave it as it is, sell it or fix it.  We have fixed all the M9 variants though we are not the least expensive - and there are reasons for that.

Anyhow, good luck with whatever your choice.  The M9 is still a nice camera.  I own a few and enjoy them.

[pedaes]

1 hour ago, dobritch said:

Leica Uk have just confirmed

Interesting first post. This does not sound like the language Leica (UK) would use. How did Leica UK have your camera to examine as they would not have invited you to send it in?

 

[jaapv]

On 12/3/2022 at 4:54 AM, dot-me-not said:

There is no question in my mind as to whether Leica should be offering repair services for M9 sensors. They should. It's handicraft work, after all, judging from the videos, with skill sets no more or less demanding than the repair of a malfunctioning M6. Repair services for old models has always been a part of Leica's heritage, has it not? These repairs are straight forward with the right tools.

It is possible to replace a cover glass with acceptable results for the user. A camera maker cannot replace it with a fair certainty that it will not meet the original specification. So it is quite understandable that they won’t. 

[pedaes]

12 minutes ago, jaapv said:

not

-not

[jaapv]

If you were right they would have been doing it for years. It would have saved them millions in replacing complete sensor units. 

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Hallo,

Look here: Leica M

[pedaes]

1 hour ago, jaapv said:

If you were right they would have been doing it for years. It would have saved them millions in replacing complete sensor units. 

If you are replying to me, I was referring to your double negative -cannot and not.