Sensor Cleaning - Not the Same Questions

I'd been cleaning my 30D sensor since it was a few days old. Bought a nice kit (albeit expensive), and since I tend to shoot clear skies, the swabs were soon used up. The tiny bottle of Sensor Clean will last a long time fortunately.

So being the frugal type and an engineer, I was looking for an alternative to the expensive swabs that the manufacturer said should only be used for one pass. I had heard of Q-tips (and some of you with good memories will recall that I used them); they are not expensive, are soft, but little bits of cotton fibre can remain, requiring a lot of blowing.

Then last week, Belmondo mentioned in a post, that one should always clean lenses with Kodak Lens Cleaning Paper - that was the eureka moment. How, I thought, could I use my Kodak Lens Paper with the cleaning solution?

The answer (for a APS-C sensor that is 15.00 mm wide) is to cut a 13 mm wide strip of stiff cardboard (like shoe box cardboard) a few inches long (forgive the fact that I've been comfortable in both metric and Imperial for thirty years).

Fold the strip of tissue lengthwise twice, and it's about the width of the sensor (and slightly wider than the cardboard strip). Fold it over the end of the cardboard, and clip it in place with a paper clip.

Note that the paper is 70 mm wide - folded lengthwise twice yields 70/4 = 17.5 mm - a bit wider than the sensor, but it's soft and readily conforms to the width of the pre-cut cardboard (13 mm).

Apply one drop of fluid and swab away. If you want to be fussy, remove the paper clip, slide the tissue to a clean location and repeat.

It works like a charm.

It really was a no-brainer - lens paper is soft enough to not scratch a lens, so it won't harm a sensor filter (it's glass), and it's one of the easiest cameras accessories to find.

The cardboard doesn't cost too much either.

That sounds like a good idea to me - and I'm happily bi-lingual in the metric/imperial measurements as well. Sadly showing my age..21 (x 2 plus a bit)(a big bit)..

David

Hey, I like this idea.. simple and elegant.

Any other comments?

Glenn NK wrote in post #2796477
lens paper is soft enough to not scratch a lens, so it won't harm a sensor filter (it's glass)

Be aware that the 30D is the only Canon DSLR model introduced in the last two years that has a protective glass cover over the sensor.

The 5D doesn't, and the dust-shakers on the XTi/400D and the new 1DmkIII don't. I wouldn't be surprised if future Canon DSLRs continue this trend of leaving off what Canon calls a "relatively expensive glass cover".

On these newer cameras, you're not swabbing a protective glass cover; you're swabbing the coatings applied to the front of the sensor assembly. There is the possibility of stripping away those coatings. Of primary concern is the dichroic "hot mirror" coating. If that coating gets damaged, the sensor will be unduly sensitive to infrared in the areas where the coating has been removed. While this might not be visible in most shots, false color will occasionally be noticed, especially on clothing made out of certain synthetic fabrics and on some white-painted surfaces.

Photographic Solutions has created a special cleaner—Eclipse E2—for sensors with exposed coatings. There's currently a sticky in this forum on the topic.

Yes I spotted that thread the other day. Was a bit alarmed as I have used the normal Eclipse fluid on my 5D. Luckily I don't swab often as I find it easier to do a bit of extra photoshopping when needed. I will look out for the Eclipse 2 fluid now though. Seems a bit ridiculous though given the expense of these cameras that Canon do not use a glass protective cover.

Ray

Rayfin wrote in post #2803490
Seems a bit ridiculous though given the expense of these cameras that Canon do not use a glass protective cover.

I'm just speculating here—I have no inside knowledge…

For the 5D, I have to assume it's because of the physical size of the cover needed.

For the dust-shaker cameras, my guess is that after Sony announced the indium tin oxide "anti-static" coating on the front of the A100 sensor, Canon saw no reason not to do likewise. I'm not personally convinced that the ITO does much for dust—some people think that it does, and others think not. But it certainly makes for good marketing specifications. Which sounds better: a sensor under glass that the user can clean, or a sensor with dust-fighting coating? And oh by the way, the latter is cheaper to make.

Doug Pardee wrote in post #2803451
Be aware that the 30D is the only Canon DSLR model introduced in the last two years that has a protective glass cover over the sensor.

Is this correct? I have read in several places that there is a lo-pass glass filter in front of the sensor on the 400/XTi and that this is what you would be cleaning, not the sensor.

You're just a ferry ride away from Vancouver - how about you come over here and help clean my sensor for me =)

PhotoFranz wrote in post #2804311
I have read in several places that there is a lo-pass glass filter in front of the sensor on the 400/XTi and that this is what you would be cleaning, not the sensor.

Yes, there's a low-pass filter. All Canon DSLRs have many layers in front of the sensor proper: the RGBG color filter array, the microlenses, the 3 components of the low-pass "anti-aliasing" filter, and the two components for infrared control.

What matters is what's on top, or at the front, depending on how you look at it. In Canon DSLRs prior to the 5D, and in the 30D, there is a glass cover to protect the whole shebang. This is what you are swabbing on those older cameras.

On the 5D, XTi/400D, and 1DmkIII, there is no protective glass cover. On those cameras, your swab is rubbing on a thin coating that Canon applied to whatever is the top layer on that particular sensor design (a low-pass filter on the 5D and XTi/400D, the IR absorptive filter on the 1DmkIII).

Eclipse fluid does not attack glass. Ordinary Eclipse fluid can—and according to Photographic Solutions President David M. Stone does—attack the coating. Accidental removal of the dichroic "hot mirror" coating located on the front of the sensor can lead to false colors in some pictures.

Ouch. Thanks, I will remember that when I get my XTi in April. I guess the next question should be... How should I clean it?

PhotoFranz wrote in post #2804454
I will remember that when I get my XTi in April. I guess the next question should be... How should I clean it?

Very carefully?

A bulb blower (Giottos Rocket-Air, etc.) should be fine.

For wet methods, Photographic Solutions has just release Eclipse "E2" fluid, which is specifically formulated for sensors with exposed coatings. It was originally developed at Sony's behest for the A100, and Sony has approved E2 for that camera. Photographic Solutions guarantees that when used as directed, E2 won't damage an XTi/400D—or they'll pay to have it repaired (if Canon won't cover it, but apparently Canon always has covered it so far). This seems to be the safest route: E2 used as directed. Formulated for exposed coatings, and guaranteed to be safe on the XTi/400D.

I don't know about the various solutions from Visible Dust. They don't say what's in them. Not that it would matter—I'm not a chemist and couldn't tell you if they'd affect the coating anyway. If I even knew for sure what the coating was (I'm fairly sure that it's indium tin oxide, same as the Sony A100). Check with Visible Dust if you want to use one of their solutions.

My personal guess is that the various brushes are probably fine, too. The coating is probably not all that delicate to not be able to withstand a gentle brushing. As for the LensPen SensorKlear, who knows?

Well, some interesting and enlightening comments. My reactions:

1. Didn't mean to alarm anyone,

2. I won't have to worry about using Eclipse E2,

3. My next camera will be another 30D,

4. Where does one learn the details of construction of various models?

5. Why would a reputable manufacturer issue and expensive camera that is subject to sensor damage, knowing full well that the vibration system is not the cure-all?