John_T
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As far as I know, electric discharge always takes the path of least resistance and requires at least the same capacity of the opposite polarity to discharge.
You aren't shuffling across a wool carpet in slick bottom leather slippers in plush polyester pants and sweater in 10% humidity, then gently kissing your girlfriend on the ear. That will definitely get you some damage.
You are blowing dry air on a little brush, thereby rubbing the synthetic brush fibers together generating a miniscule electrostatic charge, just great enough to attract/lift equally miniscule particles with no force or zap. At the same time, don't assume you are equally attracting electrostatically inert mineral dust because it may not hop on the brush like the biological/synthetic bunny rabbits.
So what all can we get inside the sensor/mirror chamber and how does it get there in normal operation?
- dust: mineral, synthetic and biological
- air pollutants: esters from plastics, automotive and industrial gases, and water soluable biological particles
Every time you open the chamber to change a lens, blow it out or whatever, there is an exchange of air and temperature. When the cavity is closed, every actuation of the shutter flaps the mirror like a sultan's slave wafted fan, stirring up whatever might be in the in there, and like any air current will create swirls at points where dust finds a hold on the mirror or sensor. Viola, dust bunnies.
If you take a flashlight and shine it on your scanner glass, you will see deposits on the underside. How does it get there in a semi-sealed box? Condensation of gases given off by plastics and air pollution, plus electrostatic charge. The same thing will happen in the camera chamber. It is just so gradual that over a long period of time you don't notice the fogging until it is pretty thick. When you will dramatically notice it is after bringing your camera out of the cold into a warm humid room and take off the lens for even a brief exchange or putting on the body cap. Then moisture may condense on mirror and sensor forming droplets that collect dust and pollutants on the surfaces forming a kind of mud, that after drying are difficult to remove. After your next shoot you are screaming where did all those spots come from? Did it yourself.
Let's dispense with the mirror right away. You aren't pixel-peeping at 200% on a 2048x1536 30" display at a macro-micro world TTL, so you won't see much of what's on it anyway. Plus every time it flaps, it's self-cleaning to the detriment of the sensor, so over the mid-term there's not much there to disturb you. Touching it equals replacing it, so don't touch it.
The sensor is a different world. Four to sixteen million little devils grabbing and eating anything that comes their way, then spitting it back at you. Dust and mud included.
So how hard is the AA plate? Don't know.
What will scratch it? Any mineral dust or abrasive particle, harder than the AA glass, on the glass or on a cleaning utensile.
What will get it off without scratching? A non-abrasive material moistened with a micro-filtered liquid capable of dissolving dried condensate and suspending particles, when gently applied, leaving the AA glass squeeky clean with no streaks or residue. High-tech stuff.
I've seen posts on other forums where Chamber Clean has practically worked wonders for photographers who have many lens changes on shoots, particularly in dusty environments. Part and parcel to a clean sensor and mirror. It only makes sense.
The Visible dust internet domain is registered in the name of the CEO of a bio-tech company specializing in bio-chips, whatever they are. In any case, this is a very high tech area which involves squeeky clean bio and pollutant free processes. If he and/or his colleagues are photo nuts like us, in the laboratory or privately, it's not much of a jump to sensor cleaning. My hit is that these guys are high tech/bio tech geeks that started a casual weekend business that absolutely swamped them after RG and MR gave them the nod. Internet math says 50 can become 50,000 in a flash. I think if anybody in Edmonton were to be so generous as to check them out, that is what he will find. They need help, not stoning. (I hope.)
Edited by John_T. on Nov 22, 2004 at 01:44 PM GMT
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I just now tried to put in an order, and upon entering my credit card info and hitting submit, the page returned a MySQL error 
