Sensor Cleaning Tips by Canon

[Hogleg 44]

Finally, something more than a blower!
http://cpn.canon-europe.com/content/...e.do#container

[CaptainTom]

Finally a Canon site that endorses the idea of turning the camera off before changing lenses to keep the sensor from being "charged".
So many people have told me that this is "hooey".

[billbunton]

Well, I've never exactly understood how the pretty much non-existent charge of a CMOS device can actually attract dust through the metal blades of the shutter. But whatever works for you :-)

[darktiger]

Originally Posted by CaptainTom

Finally a Canon site that endorses the idea of turning the camera off before changing lenses to keep the sensor from being "charged".
So many people have told me that this is "hooey".

I thought that was common knowledge, well I guess I just got use to turning the camera off when changing lens....

[jon_k]

Strange though. I thought the sensors sensed light by light hitting the sensor. (What a sentence.)

My understanding on the sensor was that it works in the reverse of an LCD screen.

It has pixels, and the light+color hitting each pixel generates a voltage. You then have a small microprocessor that measures the voltage. The pixel states and values are saved to soem RAM and then dumped out of the registers into a RAW file. Then the processor does some magic and you get a picture in a jpeg. I also think ISO works on digital by simply amplifying the current/voltage generated by the CCD. (Thus amplifing the charge, sensitivity and unfortunately the noise.)

Under this logic, current is only made in the CCD when light is hitting it. Simply turning your camera on will only make the microprocessor ready to measure voltage from the CCD. No current is put inside of the CCD. Just like a voltmeter doesn't put voltage in to a circuit.

This also explains why camera makers say don't leave your camera in a hot car then take pictures or you'll get noise. It's because the heated pixels may generate more current than their neighbors, or less. This creates noise. (Or the Texas sun in your car might melt your sensor. One or the other, I'm not sure.)

This also explains why you should wait a minute or more before you run pixel mapping functions to map for hot pixels on your camera. If you take a picture, then run pixel mapping, the heat and current generated from the previous pictures may effect how the pixelmapper maps the pixels. A pixel that was excited a second ago might still be excited and the pixelmapper might inaccurately map it as a hot pixel (since it's leaking a voltage while the rest aren't.)

I don't design CCDs for a living so perhaps my understanding of CCD design is flawed, but it aligns with everything else camera makers say (Dont pixelmap after you take pictures, dont get the CCD hot unless you like noise, etc)

Anyone who has more technical understanding care to explain? I'm pretty sure thats the gist of CCD operation.

Lucky the Olympus bodies have a dust shield in front of the CCD that vibrates each time you turn it on flecking would-be-dust away. I haven't had a dust problem yet.

The rest of that article seems to be a total advertisement for VisibleDust (on page 2). Wonder how much they paid for that endorsement by Canon. I've read many users reporting that VisibleDust products are cheap and fall apart like crazy.
http://forums.dpreview.com/forums/re...ssage=18511930 Ironically one from a Canon user.

I once knew of a thread on ThePhotoForum that had links to all sorts of accounts like this but can't seem to find it. Everyone else in the thread has similar experiences to the one I linked above though. Don't think I'll buy the product soon. DUST-AID seems better though the ripping sound the adhesive makes is scary. Better than a brush falling apart inside your camera with bristles going everywhere though!

[ShaneKislack]

Maybe I've had good luck, but I've never had any sensor issues. I change lenses with the camera on...and once I removed a piece of fuzz with sharp tweezers. I even bumped the sensor with the tip....no damage.

Oh, yeah...I've never had to clean the thing either. 4 yrs and going.

[jonnydonut]

thanks for the link

[mmcaleer]

This is a first. I though Canon always claimed your camera would blow up or something similar if you even thought about getting close to the sensor.

[txphotog]

A little of topic but does anyone know of a USA version of that site? Ive noticed it was the Canon Professional Network but only available to Europe.

[CaptainTom]

I never knew there were so many microphotoelectric engineers on this forum.

But then again, I never asked. I wonder how many Canon has ? (TPFIC)

[jon_k]

Originally Posted by CaptainTom

I never knew there were so many microphotoelectric engineers on this forum.

But then again, I never asked. I wonder how many Canon has ? (TPFIC)

If thats a riff on me, no I'm not an engineer let alone electrical, let alone photoelectric!
I just had a certain understanding [misunderstanding?] of this technology.

However... here's a supporting claim. When you turn the camera on, that allows voltage to be drawn by the sensors. Opening the lens and cleaning your sensor exposes your sensor to light (thus the sensors generate current - positive charge = dust attraction.) This is a real possibility here to be considered.

I don't claim to have any background in this technology. My field is computers. If anyone /does/ have a background to credit or discredit my claims I beg you to post. I'd definitely welcome the comment of a knowledgeable camera technician. Even better if you've got a degree in engineering.

You gotta admit Canons article is almost a pure plug for visibledust though since the entire second page was allotted about their product. Thats a lot of space to cover a single product, whereas the first page covered multiple not-so-good methods of cleaning. You'd think on the second page they'd also cover DUST-AID and other high end alternatives. Definitely seems like an endorsement for visible dust. In this case I doubt the engineers were consulted here.

I'm not saying either way that your theory is hooey or that I'm a wanna-be who doesn't know what I'm talking about. Only an engineer could set this straight. Anyone know an engineer?

[robert t]

Jon you nailed it. Almost anything has the ability to build static electricity and something that has electricity passing through it definitely builds a charge although its very low it makes no difference to the dust that has and opposing charge. Powering down the camera will not eliminate the static but would help be turning off the active voltage.

[portrait]

Do you also have any idea where I can buy a new lens cap? I lost mine the last time we went to the beach. This may sound out of place but I just thought this is related to lenses. Please help.

[billbunton]

Nope, not gonna go there...

[Cope]

Originally Posted by portrait

Do you also have any idea where I can buy a new lens cap? I lost mine the last time we went to the beach. This may sound out of place but I just thought this is related to lenses. Please help.

You need to be more specific, but try eBay if local dealers can't help. KEH in Atlanta, GA usually has like new caps, but s&h to Australia might be expensive.