Brushing the sensor

[JimH]

Oops.

I really mistyped (is that the same as misspeaking - only while keyboarding?).

I didn't mean the actual Sensor Brush (TM). I've read Petteri's write-up and I believe that he's on the right track. I guess I should have said "A brush for the sensor a-la Petteri".

When I first read about the CopperHill and Sensor Brush (TM) methods, I felt as if both had good merit. CopperHill for stuff that's really stuck to the sensor, and Sensor Brush (TM) for "normal" use. Personally, I've had dust problems, but never yet anything that was glued to the sensor and required solvent-wiping.

My impressions are similar to Petteri's about the Sensor Brush (TM) products and the Copper Hill method.

The CopperHill method seems like the way to go if you need to remove gunk or “stuck-on” particles, but it seems a bit extreme for just getting dust off.

The Sensor Brush (TM) products sound more reasonable for what you’ll normally need to do. It seems like it should be safer and a lot less work.

It appears that the Sensor Brush (TM) folks are on to a good method of getting dust loose from the sensor and it appears that they've thought about the various pitfalls of brushes in general, and they've found a brush that works for the purpose.

But I, too, am somewhat disturbed by the lack of any concrete description of what, exactly, they're doing to either manufacture or process their brushes. I'd like to know more than what their website is telling me. This doesn’t mean that they're doing anything wrong or totally BSing us, but their site doesn't convince me that they are really doing anything better than what Petteri describes.

And I’m a cheapskate too. I know the camera was expensive, but I still can’t bring myself to shell out a hundred bucks for a couple of brushes – especially if I feel that I could do as well for a lot less.

But the actual Sensor Brush (TM) may not be a bad product and even though the price is high, if you don’t want to go to the trouble yourself of finding, cleaning, and testing an “off the shelf” brush, it may well be the way to go.

Keep in mind that I’m no expert at all on this whole subject. I started reading this thread precisely because I am searching for an answer to the dust removal problem. I sort of got sidetracked when I read about the use of a Zerostat on the sensor and just felt that I ought to voice my concerns about that procedure.

In short, I really do like what Petteri has described and I’m going to try his method, I guess.

I'd love to hear more from people who are using or expanding on his technique. I applaud Gabor for his work and for sharing it with us all. I really do think everyone deserves a good answer to the whole dust-on-the sensor problem.

Jim H.

I'm leaning toward a sensorbrush at this point.

Why? Why do you think a Sensor Brush (TM) is any better than what
Petteri describes?

 

[GaborSch]

I'm sorry that this is so long

I too am not living off the posting activities here

Anyway, I try to concentrate on what is relevant.

Make no mistake, you are directing a stream of charged molecules (ions) into your camera body

Of course; that's the point.

Do you believe that the inoized air molecules which are being drawn
away from the needle are going to just strike the glass plate and be
annihilated in some magical manner just because that glass is an insulator?

You again are ignoring the fact, that the ionizer generates both positive and negative ions. It is not relevant, that this happens sequentially.

I've seen a small field effect transistor destroyed by holding a static
charged styrofoam cup about ten centimeters away from it.
How did that transistor-destroying static charge get transferred from
the cup to the transistor?

Irrelevant. The styrofoam had unbalanced charge (probably negative).

Re the effect of the FET: most probably the field of the charge was too much for that transistor. I don't believe, that any relevant charge transfer took place, not even if you charged the styrofoam by a Van de Graf generator.

Here is the problem. The ionizer does not generate any voltage; it
generates unbalanced charges.

This is incorrect. An electrostatic voltmeter connected between
the needle on the Zerostat and the handle you're squeezing will
show tens of thousands of volts

Uh-huh. Getting closer to it. This is a very important point. The Zerostat does not generate any voltage, but charge. The charge has an electric field, the strength of which is the voltage. This charge has a strong electric field on the tiny needle. However, as it spreads out with the air, the strength of the field is rapidly decreasing (at least proportionally to the cube of the distance). Furthermore, as it meets any metal part, it gets distributed everywhere and the voltage drops accordingly.

You mentioned, that if you put your finger close enough to the needle, a sparkle will "jump over". That's right; the reason is, that at that point the voltage is very high. Try to make a sparkle in the air!

Even if you "shot" directly into the cavity, the voltage would be very low - except if you went so close to the body, that a sparkle jumps from the ionizer to the body. But I did not suggest to put the nose of the ionizer INTO the cavity.

Most of the charge in the air will not meet the body. It spreads out quite far away, and it's strength diminishes.

Back to another point: the effect of this charge on the camera. This charge is only a fraction of what can accumulate in and on your body when walking on a carpet, for example (a sparkle from over an inch distance can jump from your body, but not from this ionizer). Still, you can touch your camera. When you are changing lens, you can touch the connectors, etc. - the charge will distribute on the camera.

There is no Faraday-cage here. You touch for example the metal part for the lens mounting, and the charge is already "inside the camera".

What I will do is to just breathe gently into it

This is, what I will never do.

That's up to you. We use humidifiers in our PCB assembly rooms and
computer rooms to keep the static at bay. Maybe that's a bad idea
all of a sudden.

I do see a difference between the air (plus the rest) what we breathe out and the air pumped out (after having cleaned or at least filtered, btw.) by a humidifier.

Likewise, I rinse my eye-glasses with water (after having washed them with liquid soap) instead of spitting on them.

--
Gabor

 

[jeffx]

2 reasons:

a) becuase the damage is incremental and may not cause immediate failure (oxide insulating layer is attacked by ESD)

and

b) because the result is probably dead pixels, and many folks may not immediately notice

and

c) becuase people who screw up their equipment quietly get them fixed (mapped-out in this case) or sell tham on eBay.

Just because you have not been made priivy to the screw-ups does not mean that the laws of physics are different for you. The whole semiconductor industry is not wrong about ESD protection. Materials that can sustain a surface charge (non-conductive materials) are not even allowed in semiconductor manufacturing/testing/storage areas. MIL-STD-1686 will scare you out of this reasoning, and you can find it on the web if you poke around.

Those pink static bags are mildly conductive, to dissipate charge.

js

The chances of damage when using "charged" tools is high.

Then how come nobody, to my knowledge, has reported damaging their
sensor using this method, despite the fact that it's well known and
been extensively used for at least six months?

Petteri
--
Me on photography: [ http://www.prime-junta.tk/ ]
Me on politics: [ http://p-on-p.blogspot.com/ ]

 

[Heath13]

n/t

 

[Qique]

I followed Petteri's description and it worked as a charm for me.

I hope you dont mind me posting the brush type here because Petteri's original thread is full.

I have used the brush "Da Vinci - Junior Synthetics - number 14, serie 304".

Worked great.

--
Happy Camping!