Reid Review on M9 sensors

[Guest jvansmit]

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Silica Gel.

 

Silica Gel doesn't help those occasions in summer (at least here in Hong Kong) when the M9 mists up when moving from an air-conditioned apartment to high humidity 35C outside temperatures.

 

My M9 & MM mist up so much in July/August that they are unusable for the first 5-10 minutes outside.

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[jdlaing]

Silica Gel doesn't help those occasions in summer (at least here in Hong Kong) when the M9 mists up when moving from an air-conditioned apartment to high humidity 35C outside temperatures.

 

My M9 & MM mist up so much in July/August that they are unusable for the first 5-10 minutes outside.

 

I realize that. I was just correcting the poster that said "silicone".

[jevidon]

What shall I say, except to roll my eyes Just because you saw a reference doesn't mean that this is an effective solution for a hot and humid climate. Even a little thought should make it obvious that it isn't.

 

Have you tried it, or is it just your opinion? Fortunately, I live in a desert so humidity is the least of our climatic issues.

[jevidon]

Silica Gel doesn't help those occasions in summer (at least here in Hong Kong) when the M9 mists up when moving from an air-conditioned apartment to high humidity 35C outside temperatures.

 

My M9 & MM mist up so much in July/August that they are unusable for the first 5-10 minutes outside.

 

You miss the point. I suggest that your M9 spends more time on the shelf than in your hands; i.e., during hours of sleeping, eating and other activities assuming you are a normal person. Every hour spent with a silica gel bag or three in a zip lock bag is an hour without humidity. It is probably the prolonged exposure to humidity you are faced with and anything to reduce total humidity exposure will benefit your M9 sensor. It's only common sense.

[jaapv]

I think a considerable number of owners in such climates keep their gear in a dry cabinet. Silicagel is not very useful in the long run, one must keep it activated by regularly drying it out in the oven.

Good for an occasional visit as a tourist when using a Pelican Case, but not for people who live there.

[jevidon]

I think a considerable number of owners in such climates keep their gear in a dry cabinet. Silicagel is not very useful in the long run, one must keep it activated by regularly drying it out in the oven.

Good for an occasional visit as a tourist when using a Pelican Case, but not for people who live there.

 

jaaspv,

Got it. Fortunately, I live in a very dry climate (winter humidity 40-60, summer humidity 10 to 25). But even my old Nikon D70s contracted the white spot disease. But what would life be without a little drama?

[jevidon]

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I ran across the following information at La Vida Leica ( New Leica "CCDgate" Scandal Afoot? | La Vida Leica!) that may not be new information to some of you, but I found in interesting that Schott knew from the get-go that the cover glass is subject to corrosion.

 

The good news is that there is an alternative Schott cover glass that can be used but would require some firmware changes by Leica because the light transmission is somewhat different. So, Leica's search for a solution may not be as remote as some thought. New sensors with an alternative non-corroding cover glass with a Leica firmware change could be a permanent solution.

 

From LaVida Leica... note...color and italic font are my choice and not in the original site:

"...The glass is behaving as Schott said it would (link is external) (that is, corrode if not protected). As we understand it, there are a lot of cameras coming into customer service with this problem now. Unfortunately, the only fix for this cover glass issue is to replace the entire sensor, circuit board and all, as it's one assembly. The cover glass alone cannot be replaced - at least not without the help of a sensor manufacturer. The original producer, Kodak - has since filed for bankruptcy and sold the sensor assets to Truesense Imaging (link is external), who in turn was recently acquired (link is external) by On Semiconductor (link is external). It's a mess.

 

One solution is to modify the KAF-18500 sensor (link is external) to utilize Schott's BG18 cover glass in place of the current S8612. It has the same refraction index, is not affected by humidity, has a similar sharp IR cutoff and slightly lower thermal expansion characteristics. However, it is slightly less efficient in transmitting visible light, which would require that camera firmware be updated to change the exposure calibration. ...."

[jdlaing]

I ran across the following information at La Vida Leica ( New Leica "CCDgate" Scandal Afoot? | La Vida Leica!) that may not be new information to some of you, but I found in interesting that Schott knew from the get-go that the cover glass is subject to corrosion.

 

The good news is that there is an alternative Schott cover glass that can be used but would require some firmware changes by Leica because the light transmission is somewhat different. So, Leica's search for a solution may not be as remote as some thought. New sensors with an alternative non-corroding cover glass with a Leica firmware change could be a permanent solution.

 

From LaVida Leica... note...color and italic font are my choice and not in the original site:

"...The glass is behaving as Schott said it would (link is external) (that is, corrode if not protected). As we understand it, there are a lot of cameras coming into customer service with this problem now. Unfortunately, the only fix for this cover glass issue is to replace the entire sensor, circuit board and all, as it's one assembly. The cover glass alone cannot be replaced - at least not without the help of a sensor manufacturer. The original producer, Kodak - has since filed for bankruptcy and sold the sensor assets to Truesense Imaging (link is external), who in turn was recently acquired (link is external) by On Semiconductor (link is external). It's a mess.

 

One solution is to modify the KAF-18500 sensor (link is external) to utilize Schott's BG18 cover glass in place of the current S8612. It has the same refraction index, is not affected by humidity, has a similar sharp IR cutoff and slightly lower thermal expansion characteristics. However, it is slightly less efficient in transmitting visible light, which would require that camera firmware be updated to change the exposure calibration. ...."

 

Kodak's sensor company was ISS.

Truesense Imaging became the name of the company after Kodak sold it to Platinum Equity as a free standing company before Kodak filed bankruptcy.

[jevidon]

Kodak's sensor company was ISS.

Truesense Imaging became the name of the company after Kodak sold it to Platinum Equity as a free standing company before Kodak filed bankruptcy.

 

And Truesense was purchased recently by On Semiconductor just to keep the record straight. On Semiconductor lists the M9, MM and ME CCD sensor in its inventory.

[jdlaing]

And Truesense was purchased recently by On Semiconductor just to keep the record straight. On Semiconductor lists the M9, MM and ME CCD sensor in its inventory.

 

That inventory is for the public and over and above what is set aside and maintained for contract purchases and supply.

[semi-ambivalent]

Can someone here tell a layman (me) why a glass is "corroding"? Other than from a few fluorine compounds I was always under the impression that glass didn't do much of anything.

 

Thanks,

s-a

[jaapv]

Glass can certainly corrode. Just look at glass that has turned milky in the dishwasher.

[jdlaing]

Glass can certainly corrode. Just look at glass that has turned milky in the dishwasher.

 

I believe that's calcium.

[jdlaing]

Can someone here tell a layman (me) why a glass is "corroding"? Other than from a few fluorine compounds I was always under the impression that glass didn't do much of anything.

 

Thanks,

s-a

 

It doesn't. Some acids and alkiline compounds can with heat, but glass is pretty impervious.

I think the term corrosion was just convenient.

 

"Glass is much more resistant to corrosion than most materials, so much so that it is easy to think of it as corrosion-proof. Glass windows after several years exposure to the elements remain clear and apparently unaffected. Glass bottles hold a wide range of liquids that would dissolve other materials. In the laboratory, reactions are carried out in glass beakers and flasks without damage to the beakers or contamination of the solutions reacting.

.

But, in spite of these indications that glass is indestructible by chemical attack, under certain conditions it will corrode, even dissolve. In these cases, it is important to choose the right type of glass, since some are more corrosion resistant than others. Only a few chemicals aggressively attack glass -- hydrofluoric acid, concentrated phosphoric acid (when hot, or when it contains fluorides), hot concentrated alkali solutions and superheated water. Hydrofluoric acid is the most powerful of this group; it attacks any type of silicate glass. Other acids attack only slightly; the degree of attack can be measured in laboratory tests but such corrosion is rarely significant in service for acids other than hydrofluoric and phosphoric.

.

Acids and alkali solutions attack glass in different ways. Alkalis attack the silica directly while acids attack the alkali in the glass."

[Lenshacker]

I ran across the following information at La Vida Leica ( New Leica "CCDgate" Scandal Afoot? | La Vida Leica!) that may not be new information to some of you, but I found in interesting that Schott knew from the get-go that the cover glass is subject to corrosion.

 

The good news is that there is an alternative Schott cover glass that can be used but would require some firmware changes by Leica because the light transmission is somewhat different. So, Leica's search for a solution may not be as remote as some thought. New sensors with an alternative non-corroding cover glass with a Leica firmware change could be a permanent solution.

 

From LaVida Leica... note...color and italic font are my choice and not in the original site:

"...The glass is behaving as Schott said it would (link is external) (that is, corrode if not protected). As we understand it, there are a lot of cameras coming into customer service with this problem now. Unfortunately, the only fix for this cover glass issue is to replace the entire sensor, circuit board and all, as it's one assembly. The cover glass alone cannot be replaced - at least not without the help of a sensor manufacturer. The original producer, Kodak - has since filed for bankruptcy and sold the sensor assets to Truesense Imaging (link is external), who in turn was recently acquired (link is external) by On Semiconductor (link is external). It's a mess.

 

One solution is to modify the KAF-18500 sensor (link is external) to utilize Schott's BG18 cover glass in place of the current S8612. It has the same refraction index, is not affected by humidity, has a similar sharp IR cutoff and slightly lower thermal expansion characteristics. However, it is slightly less efficient in transmitting visible light, which would require that camera firmware be updated to change the exposure calibration. ...."

 

That information was posted here in this forum before "La Vida" copied it to their web page, and I also posted here with a bit more detail:

 

True Sense Imaging, maker of CCD's for the M-E and M Monochrom, now ON Semiconductor - Page 2

 

I'm not sure how many other people looked at Schott BG-18, I picked it as the refractive index is the same as S8612 and it is listed as being more resilient to corrosion. It's just one of several possible remedies.

[Guest jvansmit]

You miss the point. I suggest that your M9 spends more time on the shelf than in your hands; i.e., during hours of sleeping, eating and other activities assuming you are a normal person. Every hour spent with a silica gel bag or three in a zip lock bag is an hour without humidity. It is probably the prolonged exposure to humidity you are faced with and anything to reduce total humidity exposure will benefit your M9 sensor. It's only common sense.

 

Fortunately, I have very effective built-in Daikin dehumidifiers in my flat which I use when the aircon isn't switched on. I'm more worried about the approx 20-30 hours per week spent outside with my cameras in high humidity periods.

[jaapv]

You cannot compare optical glass to laboratory glass; just look at lens fungus.

It doesn't. Some acids and alkiline compounds can with heat, but glass is pretty impervious.

I think the term corrosion was just convenient.

 

"Glass is much more resistant to corrosion than most materials, so much so that it is easy to think of it as corrosion-proof. Glass windows after several years exposure to the elements remain clear and apparently unaffected. Glass bottles hold a wide range of liquids that would dissolve other materials. In the laboratory, reactions are carried out in glass beakers and flasks without damage to the beakers or contamination of the solutions reacting.

.

But, in spite of these indications that glass is indestructible by chemical attack, under certain conditions it will corrode, even dissolve. In these cases, it is important to choose the right type of glass, since some are more corrosion resistant than others. Only a few chemicals aggressively attack glass -- hydrofluoric acid, concentrated phosphoric acid (when hot, or when it contains fluorides), hot concentrated alkali solutions and superheated water. Hydrofluoric acid is the most powerful of this grobup; it attacks any type of silicate glass. Other acids attack only slightly; the degree of attack can be measured in laboratory tests but such corrosion is rarely significant in service for acids other than hydrofluoric and phosphoric.

.

Acids and alkali solutions attack glass in different ways. Alkalis attack the silica directly while acids attack the alkali in the glass."

[Lenshacker]

http://www.schott.com/advanced_optics/english/download/schott-vg20-nir-absorbing-optical-filter-glass-2013-eng.pdf

 

Slide 16 of the above presentation shows corrosion of an IR absorbing glass containing Phosphate vs an IR absorbing glass with Fluoro-Phosphate.

 

Various elements are introduced to glass to control the spectral characteristics. Some of these will corrode. It will be interesting to see which new cover glass is used for the long term solution for the KAF-18500, or if a new sealing process is used. S8612 has superior optical qualities for a bandpass filter compared with the other choices.

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Hallo,

Look here: Leica M

[jdlaing]

You cannot compare optical glass to laboratory glass; just look at lens fungus.

 

Lens fungus grows inside the lens. Not on the outside. You could grow the same fungus inside laboratory glass in the same conditions.

[Lenshacker]

Fungus grows on the surface of the glass, including the front and rear surfaces. The spores are foreign to the lens. The corrosion of the cover glass is caused by the chemistry of the glass reacting to heat and humidity.