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Sensor Corrosion Analysis and Fix [Merged]


rramesh

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1 hour ago, dllewellyn said:

You can't blame Schott.  They will tell you that certain sorts of glass oxidize.  It is just part of the chemical structure of the glass.  It is up to the user to decide if they want to use the glass raw, coat or do whatever.  Even glass that doesn't oxidize gets haze and such over time.  For that matter, glass is not really a solid (no exact melting point).  Look at old windows, and you can see the glass slowly sags.

We were taught during lectures (admittedly a long time ago!) that the isssue of ‚Äúold glass in windows‚ÄĚ was a canard. The timeframe for glass to actually ‚Äúslump‚ÄĚ was a veeeerrrryyy long time, much longer than the few hundred years or so for the supposedly sagging panes with their thicker lower portions and thinner tops.

The reason given for the glass appearing to have sagged was that glass was cast in a spun disc (hence the bulls-eye roundel panes from the centre which were the cheapest pieces) and could often tapered slightly from centre to edge and also have circular wave-like ridges from being spun . Once the glass was cut into panes for a window it would tend to have one thicker edge/end and a glazier would always place this at the bottom of the opening for the simple practical reason that the pane would then stand in place while applying the sprigs/putty rather than tending to fall forward under gravity if placed with the thick edge at the top......

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57 minutes ago, NigelG said:

We were taught during lectures (admittedly a long time ago!) that the isssue of ‚Äúold glass in windows‚ÄĚ was a canard. The timeframe for glass to actually ‚Äúslump‚ÄĚ was a veeeerrrryyy long time, much longer than the few hundred years or so for the supposedly sagging panes with their thicker lower portions and thinner tops.

The reason given for the glass appearing to have sagged was that glass was cast in a spun disc (hence the bulls-eye roundel panes from the centre which were the cheapest pieces) and could often tapered slightly from centre to edge and also have circular wave-like ridges from being spun . Once the glass was cut into panes for a window it would tend to have one thicker edge/end and a glazier would always place this at the bottom of the opening for the simple practical reason that the pane would then stand in place while applying the sprigs/putty rather than tending to fall forward under gravity if placed with the thick edge at the top......

I mentioned the Hagia Sophia for a reason. At the time of the construction, the builders were unsure about the  stability of the foundation. It was an extremely innovative building at the time. So they incorporated strips of glass that would signal any deformation by breaking. Nowadays one can see the glass strips, bent in S-shape over the centuries by the slow settling of the building.

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4 hours ago, jaapv said:

As argued against above... who is to blame, if blame there is?  Leica, who set out the parameters with rangefinder lenses in mind? Kodak,who formulated the production specifics? Or Schott who provided the corrosion-proofed glass? 

I would say that the blame on the bad design decisions has to be shared together by both Leica and Kodak. They both let the end customers down in an inexcusable way.

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4 hours ago, jaapv said:

Even when the customers had to pay, it was 60%. 

It used to be that Leica took care of their customers first (customers paying 0% to get their right to a working camera). Then the customers suddenly had to pay 60% too much. Today they have to pay 100% too much.

I love Lecia as a company, and most of their great products, but this is honestly not excusable in any shape, way or form IMNSHO.

Edited by martinot
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12 hours ago, DandA said:

I posed this question to Kolari. They mentioned their replacement M9 cover glass reduces the Leica sensor stack by 0.2mm, further improving on it’s excellent corner sharpness.  I assume when the sensor stack it changed in thickness, the camera's focusing has to be readjusted?  If that's the case and assuming its done, does that in turn mean every M lens one owns also has to be recollimated or adjusted to match the camera's newly adjusted focusing?  If that's the case, it would make more sense to simply have the replacement coverglass being the same thickness as the original and avoid needing the both the camera as well as lenses readjusted for focusing.  Simply trying to get an understanding of all this.

Dave (D&A)

I do not have any M9 (was fortunate two years ago to resist a tempting deal on the M-E), but I would personally stay away from such a change to the sensors stack if it was my own M9.

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4 hours ago, dllewellyn said:

You can't blame Schott.  They will tell you that certain sorts of glass oxidize.  It is just part of the chemical structure of the glass.  It is up to the user to decide if they want to use the glass raw, coat or do whatever.  Even glass that doesn't oxidize gets haze and such over time.  For that matter, glass is not really a solid (no exact melting point).  Look at old windows, and you can see the glass slowly sags.

Totally agree. The blame is 100% to be split between Leica and Kodak.

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The prime contractor has Total System Design responsibly.   They need to have the right engineers to oversee every detail.  That said I am grateful to Leica for the M9. I have dragged my feet on trading in my M9 for an M10.  I prefer to keep my M9 and I will use one of these to get it repaired.  

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I'm really glad there's finally an option, a more affordable one at that. I have a M9P with a heavily corroded sensor (bought in Singapore, where the weather accelerates the issue), and kept looking at replacing the sensor for some time, but always delaying due to the price (I can - almost - buy a 2nd hand M9 with replaced sensor with the money that Leica Singapore was asking for the replacement for mine). I happily shoot with it at f2 and below, where it doesn't show the spots, but I would really like it fixed. 

My concern is the legal aspect of it - do you think Leica will intervene to stop these contractors?

It looks a bit "too good to be true" (especially taking into consideration the options offered: repair/ full spectrum/ monochrome), and I'm reluctant to get my hopes up... 

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4 hours ago, criolf said:

I'm really glad there's finally an option, a more affordable one at that. I have a M9P with a heavily corroded sensor (bought in Singapore, where the weather accelerates the issue), and kept looking at replacing the sensor for some time, but always delaying due to the price (I can - almost - buy a 2nd hand M9 with replaced sensor with the money that Leica Singapore was asking for the replacement for mine). I happily shoot with it at f2 and below, where it doesn't show the spots, but I would really like it fixed. 

My concern is the legal aspect of it - do you think Leica will intervene to stop these contractors?

It looks a bit "too good to be true" (especially taking into consideration the options offered: repair/ full spectrum/ monochrome), and I'm reluctant to get my hopes up... 

How on earth could Leica stop these repairs?  There is no conceivable legal objection to have whomever you choose repair or modify your personal property.
And even if there were, it would be the most stupid thing to do for Leica.

Sensor filter glass replacement has been possible for a long time, we even have members on this forum with modified cameras and if you search for websites that specialize in IR photography you'll find that this modification is quite common. The firms mentioned in this thread are well-reputed.

 

Anyway, let's look at the bottom line:

This repair option is a wonderful opportunity to give these cameras a new lease on life. After all, they are all-time great cameras. When I moved into the APS-C system I sold the M240 which I only bought to get rid of the Visoflex 3. My M9 and MM1 are never-sell cameras.


The only regret I have now is that my M9 has a second-generation sensor. I would love to have a full-spectrum one.ūü§ď

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I can modify for full spectrum as well.  Of course, then you will typically be using filters depending on what you want the camera to see.  Another point, because of the glass Leica used in the M9 cameras, if the users want to do UV photography, their M9 cameras can see UV light way, way more than other cameras.  Silicon sensors are not very sensitive to UV light, but a normal ICF has a sharp UV cutoff. The early M9's do not (I don't know about the later ones).  A monochrome version with no CFA or microlenses will see UV light even better (6x), but if you have an early M9 and want to experiment on the UV side, your camera can do it.  The first factory M9 is a UV-Visible camera, but keep in mind that the image sensor response is rolling off in the UV.

However, I don't know the response function of the 1st vs 2nd generation M9 sensors.  It would be interesting to test early versus late M9 cameras.  At least the first 66,000 cameras were 1st generation ICF's  with coverglass that was problematic but also passed UV quite well.  Maybe Leica could let us know when things changed.

Edited by dllewellyn
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3 hours ago, jaapv said:

How on earth could Leica stop these repairs?  There is no conceivable legal objection to have whomever you choose repair or modify your personal property.
And even if there were, it would be the most stupid thing to do for Leica.

Sensor filter glass replacement has been possible for a long time, we even have members on this forum with modified cameras and if you search for websites that specialize in IR photography you'll find that this modification is quite common. The firms mentioned in this thread are well-reputed.

 

Anyway, let's look at the bottom line:

This repair option is a wonderful opportunity to give these cameras a new lease on life. After all, they are all-time great cameras. When I moved into the APS-C system I sold the M240 which I only bought to get rid of the Visoflex 3. My M9 and MM1 are never-sell cameras.


The only regret I have now is that my M9 has a second-generation sensor. I would love to have a full-spectrum one.ūü§ď

Jaap, if there are forumers close to Leica, we should see if Leica could work out a contracting arrangement with Kolari or other 3rd party to replace sensor glass. This seems to be the only weak link in an otherwise usable and well liked M model. The risk is nominal and the value to customers immense. 
 

Leica did introduce several premium limited edition variants of the M9 which will have the same issue. 
 

Such service is needed from Leica for cameras that should last longer than cheaper models from other vendors. 

Edited by rramesh
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19 hours ago, Einst_Stein said:

How would it affect raw conversion?    

Using a "normal" raw converter such as Lightroom will work ok, even though it will do a demosaicing process that is slightly counterproductive, but for maximum sharpness you want a raw converter that makes specific provision for debayered sensors, e.g., AccuRaw Mononchrome. Here's a comparison (using a MaxMax converted camera, btw): https://www.mcguffogco.com/accurawmonochromemac#difference

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It's wonderful that there are options available. However, Leica SHOULD have figured these options out and provided them as options to customers. At the least they should have posted the options on their site if they didn't want to get involved. I would expect any manufacturer to at least do that (spend some time investigating options, contact some companies, and see if some kind of repair option could be viable to recommend to customers). 

Pretty cool to have the option of having a Monochrom or just a working camera though. I have a new sensor which is working now but it's nice to think that if something happens I will still have some options. 

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12 hours ago, criolf said:

I'm really glad there's finally an option, a more affordable one at that. I have a M9P with a heavily corroded sensor (bought in Singapore, where the weather accelerates the issue), and kept looking at replacing the sensor for some time, but always delaying due to the price (I can - almost - buy a 2nd hand M9 with replaced sensor with the money that Leica Singapore was asking for the replacement for mine). I happily shoot with it at f2 and below, where it doesn't show the spots, but I would really like it fixed. 

My concern is the legal aspect of it - do you think Leica will intervene to stop these contractors?

No. Nothing to worry about. They have no want or reason to do so, but more importantly to answer your direct question; they also have absolutely no legal possibility to do so either.

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