(OK, that's frustrating. I just wrote the entire article, clicked "Publish" and it wasn't there. Grrr.)
So here goes (again):
FacZen Photography Tips
Clean your DSLR Sensor
Here's the deal. Every time you change lenses, you open the camera body to the air. The air, which is full of gunk like dust bunnies, pollen, sand, greasy smoke, pollutants, and well-meaning camera owners' spit. In fact, unless you have one of those high-end lenses (you know, the Canon "white L-glass" ones or the Nikon lenses that cost you over $1000), every time you zoom or focus your lens, you're sucking dust inside.
Now that doesn't get directly on your sensor. See, unless you’re taking a picture, the mirror is down, covering the sensor, airtight. Anyway, the sensor itself (which is a really, really precise Integrated Circuit which costs more to replace than you paid for your camera), is covered with a protective glass or mineral crystal cover, so dust and gunk gets on THAT, not on the sensor itself. Still, even the old D-70 has 6 million little points on it that detects light, so a flake of dust smaller than you can imagine can cover a bunch of them.
No, it doesn’t get on the sensor protector when you change lenses, it gets on it when you take a picture and the mirror, moving in that compartment, moves the air around inside and the dust floats everywhere.
The newer generation cameras, like the D300, have built-in automatic sensor cleaners which essentially vibrate the sensor assembly and shake the dust off. Still, it’s in there, and eventually you’ll be bitten by the dust bunny.
So it’s time for me to say this: If you do anything as a result of this article and you damage your camera, IT’S YOUR FAULT. It’s not my fault. I told you not to do it. I told you to send your camera in. Don’t come crying to me.
That said, it ain’t Rocket Science. That sensor protector is HARD stuff. It ain’t diamond, so you CAN scratch it or damage it, but it isn’t that easy to do. Still, if you’re going to do anything, be gentle. Be careful.
I do want to caution you, though.
How often do you have to clean it?
How do you know if you need to clean your sensor?
Where do you get a sensor cleaning kit?
I started with some research on the Internet and learned that I should use a nylon brush, and blow air through it to statically charge it, then cautiously swipe the sensor. However I looked further and found what I think is an easier and a better method. I found “Copper Hill Images” at http://www.pbase.com/copperhill/ccd_cleaning (that’s an underscore between “ccd” and “cleaning”). I bought their “Basic” kit which cost me about $35 including shipping. You get a “SensorSwab”, a package of PecPads, some Eclipse liquid and lots of instructions.
Preparing to clean your sensor
• You’re going to need to lock up your mirror. Learn how. On the Nikon, it’s in the menu and the instruction book cautions you to us an AC power source so it doesn’t snap down in the middle of the procedure. I think that’s overkill – but I do make sure I have a fresh battery in the camera when I’m working on it.
Actually cleaning it
Follow the instructions they give you. Basically, you want to lock the mirror up, then swipe the swab across the sensor once, then back the other way (using the other side of the tip). Don’t give into any temptation to scrub things. Swipe with about the same amount of pressure you would put on a felt pen.
Put the lens back on, shoot another test picture, and see how you did. If there’s still objectionable dust there (there will always be some...) do it again. If you’re really cautious, change the PecPad.
The bottom line
It’s not difficult, you just have to be careful. You don’t have to do it as often as you think, but it is a necessary task from time-to-time. As I said, it “ain’t rocket science”.
So have fun, and don’t do anything I wouldn’t do.