The Great 'Indium Tin Oxide Sensor' hoax

wall of text does 999 damage!!! :P

Damn I must be wierd I can read it with no problem. Must be a bunch of editors or school teachers reading it, not replying to the question but jumping on the script format. Owell I thought it was interesting enough to read without belittling the origional poster.

Ukuleleman wrote in post #4024621
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I punctuated it all again, but nothing happens when I save the modified version, sorry, it beats me!

you're editing html formatting.

Cut and paste it all into notepad and do it there. It will come out right.

Okay, so it there an answer I missed in the thread? Does the XTi have this coating, and do some of the wet cleaning solutions pose a danger to this coating?

Now that there's a legible version of the original post (thanks, msowsun), maybe I can straighten this mess out.

First, as Box Brownie mentioned, there is the question of what you mean by "sensor". From your point of view as a consumer, you don't really care if what you damage is the sensor proper or a glass filter layer or a coating or whatever—the repair cost from Canon is the same.

Essentially all sensor assemblies include some kinds of additional glass layers; all Canon sensor assemblies do. But again, that isn't really relevant. If you damage any part of the assembly, Canon will replace the entire assembly. What matters is just how delicate is the assembly, in terms of cleaning.

Most older DSLR sensor assemblies were topped off with a protective cover glass. When you clean those sensor assemblies, you're just cleaning glass. Your big concern there is not making things worse with streaks and such.

Recent Canon DSLR models do not have a protective cover glass. Those models are the 5D and all models with a dust-shaker. On those cameras, you are cleaning the chemical coatings on the sensor assembly. Yes, the coatings are on glass, but that isn't relevant. What matters is that you're cleaning a chemical coating applied to the glass, not plain glass.

Is this coating Indium Tin Oxide (ITO)? Canon doesn't say. What is the purpose? Canon doesn't say. My personal guess is that on the dust-shaker cameras this is indeed an ITO (or related) coating that acts as the IR hot-mirror—the XTi White Paper (page 6) shows the dichroic hot-mirror coating on the front of the shaken layer. My personal guess is that for marketing purposes, the ITO coating is also considered to be a conductive anti-static coating—ITO is used for both purposes (hot mirror and conductive coatings) in other industries. Evidence strongly suggests that the coating on the 5D is indeed the IR hot-mirror coating, and my personal guess is that on the 5D this is made with something different from what is used on the Canon dust-shaker cameras.

I have seen maybe a dozen reports from people who have damaged the hot-mirror coatings on their 5D sensors during cleaning. These unlucky folk all seem to have been using either chemical wet-cleaning or adhesive cleaners. There is no question in my mind that, regardless of tests and claims to the contrary by some cleaner manufacturers, the 5D sensor assembly is susceptible to hot-mirror coating damage during cleaning.

On the other hand, I have seen no reports of hot-mirror coating or any other damage to the sensors on Canon dust-shaker cameras. Given the number of XTi/400D units out there, and the length of time that they've been out there, this is fairly impressive. Maybe a lot of XTi/400D users don't know what hot-mirror coating damage looks like, but I'd still expect to have seen some reports of trouble by now. So while there certainly is a theoretical cleaning hazard on the Canon dust-shaker cameras, apparently it's not something that is happening in practice.

I did not read all replies. But as several pointed out, yes, all DSLRs have a glass cover on the sensor. This cover is sometimes refered to as "IR filter". It cuts of infrared light.

Note that this glass cover would also have some coating to reduce reflection (just like any other glass surfaces in a lens). So the company selling the cleaning fluid may be refering to this coating instead of the coating on the actual sensor.

We're no further forward really - Doug says no glass covering the 5D/400D/40D/Mk III sensor, Pieq314 says all sensors have a glass cover.

Keith R wrote in post #4025659
We're no further forward really - Doug says no glass covering the 5D/400D/40D/Mk III sensor, Pieq314 says all sensors have a glass cover.

Doug said that those cameras do not have a CLEAR glass protective cover over the filter that all sensors have. No Canon DSLR sensor is sitting in there ready to be touched directly. All have at least a filter over them.

The sensor is made with a glass top. Canon then fits an IR filter. The IR filter is sometimes coated to help with light losses etc.

So the sensor is never touched. It is possible to wreck the IR filter and have to get Canon to replace it, as some have had with their 5Ds.

So in short, the OP is wrong, all sensors have a glass cover. But the coating can be damaged on the cover. It can also be replaced at cost.

Thank you.

Keith R wrote in post #4025659
We're no further forward really - Doug says no glass covering the 5D/400D/40D/Mk III sensor, Pieq314 says all sensors have a glass cover.

Ahem. I said, "Essentially all sensor assemblies include some kinds of additional glass layers; all Canon sensor assemblies do."

The question is whether the top layer is a simple protective glass cover or if it's a coated glass layer. Simple glass covers, as used on the older Canon DSLRs, can be cleaned with almost total impunity. Coated glass layers are a different matter, and the 5D sensor coating seems to be somewhat delicate.

The coatings on the Canon dust-shaker cameras seem to be fairly tough, but they are exposed coatings.

mcmadkat wrote in post #4025706
The sensor is made with a glass top. Canon then fits an IR filter. The IR filter is sometimes coated to help with light losses etc.

So the sensor is never touched. It is possible to wreck the IR filter and have to get Canon to replace it, as some have had with their 5Ds.

So in short, the OP is wrong, all sensors have a glass cover. But the coating can be damaged on the cover. It can also be replaced at cost.

Thank you.

I believe McMadkat has it right, and that all have a glass cover of some sort (whatever it's purpose - likely protection), but some have an ITO coating on this glass.

I have had my "cover" replaced because of a scratch caused by what seems to have been careless or overly agressive cleaning.

Having my filter cover replaced cost in the order of $300, and the rumour at our local camera club is that a member's 5D repair approached $2,000 for the replacement. From this it seems plausible that the 5D (and others) have a filter cover that is not removeable and/or replaceable.

I know for certain that the 30D has a removeable filter - mine is sitting on my desk as I look at it. I also know that it's not the sensor, as there are no electrical connections to/from it, and I can see through it. Correction: it has one metal tab which appears to be an electrical connection - I'm guessing it is a ground connection as there is only one.

Looking through the filter cover, it appears to be pale green in colour, although the outer side has a pink cast when viewed at angle; this would indicate that the pink colour is a coating.

Bottom line: We may debate the OP's approach to Michael, we may debate whether or not there is a glass cover, we may debate whether or not there is a coating, and debate what the coating might be.

What we can't debate is that cleaning will be required, and that it can be done, but must be done with caution.

Finally, in regard to the thread title - I don't think the word hoax is accurate - "mass confusion" might be more appropriate.

Removing the filter for IR use is fairly common, several POTN members have reported doing so themselves.

OK, if I can remove it myself, why can't I replace a scratched one myself?

-js

To replace a scratched flter, you must have a new filter. Does Canon sell these filters?

When IR-modifying the camera, you normally have to replace the filter with a different piece of glass or the AF will fail misserably. You can shim the sensor a bit if the new glass has different thickness and/or IOR.

pwm2 wrote in post #4026661
To replace a scratched flter, you must have a new filter. Does Canon sell these filters?

When IR-modifying the camera, you normally have to replace the filter with a different piece of glass or the AF will fail misserably. You can shim the sensor a bit if the new glass has different thickness and/or IOR.

Isn't this what cameras like the Canon 20Da was for?

I apologise again for the state of the original text, but three efforts to alter it proved useless and I'm not doing it again.

To 'mcmadcat' I would point out that you can't be 'wrong' unless you express an opinion.
To Genn NK I would point out that the thread title finishes with the word 'hoax?' plus a question mark, which presupposes that a question has been raised and not a point of fact, I would only add that you can debate my 'approach to Michael' until youare blue in the face, short of actually bowing down and touching my forelock I could not have been more respectful or self effacing.