So, afred peeled off the Dichroic mirror ?
But the diagram suggests that every camera has the layer exposed ! Why the disaster happened only on Afred's case ?
We are sorry to hear about your experience with Dust-Aid. Here is some information you might like to know and what we are willing to do for the small amount of people who are having this coating issue.
In 1980 the coatings industry established a minimum standards regarding single or multi-layer interference coatings which are outlined in mil-spec MIL-C-48497A. This mil-spec states the minimum durability of a coated surface regarding many aspects, most notably adhesion. Below are the adhesion durability standards which single or multi-layer coatings must meet:
MIL-C-48497A: Paragraphs 3.4.1.1 and 4.5.3.1: Adhesion
The sticky surface of a cellophane (or cellulose acetate) tape (typically by manufacturer 3M and conforming to Type I of L-T-90) is pressed firmly against the coated surface of a witness piece and over its edge. The tape is then quickly removed (slowly removed for MIL-M-13508C) at an angle that is normal to the coated surface. The coating passes the test if there is no visible abrasion and no coating has been removed.
The Canon Dichroic mirror coatings on their low pass filters meet MIL-C-48497A coating standards which are not compromised when a sensor cleaning method is used. However, the sensor cleaning industry is seeing a small number of Dichroic coatings that do not meet this standard and therefore fail, causing damage to the sensor coating.
So far Dust-Aid has seen a few of these below standard coated filters. If you discover that you have a below standard coated filter from Canon, which Dust-Aid has damaged, we will replace the damaged filter for you.
Well, all the info posted by the Dust-Aid rep has been on their website for awhile, so I think he/she was just quoting it as a reminder that they already have a policy in place. It is nice that they took the time to post it for reference.
We are sorry to hear about your experience with Dust-Aid. Here is some information you might like to know and what we are willing to do for the small amount of people who are having this coating issue.
In 1980 the coatings industry established a minimum standards regarding single or multi-layer interference coatings which are outlined in mil-spec MIL-C-48497A. This mil-spec states the minimum durability of a coated surface regarding many aspects, most notably adhesion. Below are the adhesion durability standards which single or multi-layer coatings must meet:
MIL-C-48497A: Paragraphs 3.4.1.1 and 4.5.3.1: Adhesion
The sticky surface of a cellophane (or cellulose acetate) tape (typically by manufacturer 3M and conforming to Type I of L-T-90) is pressed firmly against the coated surface of a witness piece and over its edge. The tape is then quickly removed (slowly removed for MIL-M-13508C) at an angle that is normal to the coated surface. The coating passes the test if there is no visible abrasion and no coating has been removed.
The Canon Dichroic mirror coatings on their low pass filters meet MIL-C-48497A coating standards which are not compromised when a sensor cleaning method is used. However, the sensor cleaning industry is seeing a small number of Dichroic coatings that do not meet this standard and therefore fail, causing damage to the sensor coating.
So far Dust-Aid has seen a few of these below standard coated filters. If you discover that you have a below standard coated filter from Canon, which Dust-Aid has damaged, we will replace the damaged filter for you.
Quite honorable and respectable for DA to come forward like this.
I think one thing to note, according to the laws of physics, is that even an improperly applied coating is more likely to withstand cleaning swipes parallel to the coated surface, as opposed to adhesion/suction pulls at right angles to the surface.
That said, I'd imagine that the primary risks of the parallel swipes is scratches due to insoluable mineral dust, and the right angle pull being more from the power of suction due to too firmly pressing before lifiting, rather that the stated minimal adhesion.
DavidP wrote:
I believe that they have completed their study, and that the conclusion was that IF you pulled off the coating using this method, then the coating must have been applied incorrectly.
Yea, right!!
Nonsense. I can't believe people still buy these crap products for sensor cleaning. GET an air bulb!! If that doesn't work, have Canon clean the damn thing.
How folks get this magical dust on thier sensors that won't blow off is simply beyond me.
On the other hand, the continued sale of these nonsensical overpriced crap products does reaffirm my belief that people who have no ethics can sell anything to people who have no good sense.
afred wrote:
Great customer service! I didn't even have to contact you. I've sent you an e-mail back on the address you e-mailed me at. Thanks!
Great customer service? Doesn't make up for a crap product that took his camera out of commission for several weeks at best. They just stepped up to protect their profits on an overpriced product. (and so far it's just words--it'll be interesting to see what happens when this 'company' gets about 200 cameras in for 'repair'.) And blaming the issue on Canon--I'd just LOVE to see what Canon has to say about it and I'd trust Canon a loooong way before I'd trust one of these fly-by-night sensor cleaning nobodys.
Let me understand the the Fact.
1. The sensor was installed in correct direction for Afred's 20D.
2. The coating can be loosly applied someitmes ( doesn't stick to the surface tightly ). And Afred got one of them.
Looks like a smoke creen from DA. From the MIL-C-48497A description:
Harsh or severe abrasion: A coated witness piece is rubbed with a standard (rubber pumice) eraser from one point to another over the same area for 20 complete cycles (40 strokes), (only 20 strokes for MIL-F-48616 and MIL-C-48497A), with a force of 2.0 to 2.5 pounds continuously applied. The length of the stroke shall be approximately equal to 3 diameters of the eraser when the diameter or area of the witness piece permits. The eraser abrasion tester shall be held approximately normal to the surface under test during the rubbing operation. Subsequent to the rubbing operation, the witness piece shall be cleaned, dried, and then visually examined. The coating passes the test if there is no visible abrasion and no coating has been removed.
Yeah, right. Rub a sensor with an eraser 20 times back and forth with a 2 pound force and if you see a scratch blame it on Canon.
Where does Canon state that their coating process is subject to the requirements of MIL-C-48497A? This situation appears to be the typical nonsense of applying a spec or reg out of context. Besides, is there no ISO for such coatings? MIL specs are less accepted these days.
EB
Edited by EB-1 on May 28, 2007 at 08:36 AM GMT (Reason: correction)
Well, we need John P's help here. John, are you there ?
Is the MIL standard spec relevant to this case ? The spec seems to be developed for the eye glasses or car windows, which get frequent physical contacts. Inside coating which is NOT supposed to touched needs to comply ?!?!
The real question is:
Canon offers cleaning ( FREE for the 1st time and charge after ). Would Afred's camera have been cleaned w/o damage by Canon ?
Asides from pulling the coating off the mirror, I wonder if the stress created when you peal the Dust Aid off will cause the inner sections of the AA filter to seperate? Would this cause distortions or soft images?
Just way too big a risk and while Dust Aid is willing to fix this camera, who's to say they will fix the next one or the next? How will they compensate for the down time required to repair the camera and who will fix it?
