Sensor-ship II: Coming to Your Sensors
OK, so you're really confident in your abilities, you're stuck in the field somewhere and have no choice, or you live for danger. Whatever the reason, you've dismissed our warnings and are going for Operation: Sensor Sweep.
Begin by activating your camera's cleaning mode. This will flip up the mirror and reveal the sensor. Check that you have plenty of juice, either from a full battery or a wall socket. Once you have the lens off and can see the sensor, you can optionally use a special loupe, or small magnifying tool, to spot the dust [source: Cameta Camera].
Shops hawk a befuddling array of sensor-cleaning schlock, much of it packaged in kits. Not all utensils are created equal, and many kits amount to expensive overkill, so we've listed the main tools below, from least invasive to direct-but-demanding.
A sensor blower is a plastic squeeze bulb with a nozzle that blows away loose dust with a puff of air. Because it never touches the surface, it is the least risky tool and the easiest one to use in the field. Unfortunately, blowing might not be enough to knock dust loose, and blown dust can redeposit (pointing the camera at the ground helps) [sources: Kelly; McHugh]. Do not use a blower that has a brush, which can retain dust and scratch the sensor covering [source: Breen]. Also avoid compressed air, which pumps out too much force and can deposit damaging chemicals [sources: Atkins; Nakoma Products; Kelly].
A sensor brush or sweep looks like a fine, flat paintbrush. Use a very light touch, starting at one end of the sensor and gliding smoothly across. Remember, you aren't scrubbing or even sweeping; rather, you're allowing the electrostatic action of the bristles to attract the dust, like a charged amber rod attracts a balloon. Clean the brush between sweeps, and don't let the brush's edges drift off the sensor or you might pick up other pollutants. All in all, a sensor brush or sweep is a good compromise tool and is handy for dusting your focusing screen [sources: Breen; Kelly; McHugh].
A sensor stamp or pen has a deformable tip (usually made of silicone) that hugs individual dust particles. To use, simply press it against the surface of your sensor and watch the dirty lovefest begin. Because you press instead of dragging, you're less likely to cause unwanted scratches. Avoid the versions that use adhesives, which can leave sticky residue behind [source: McHugh].
A sensor swab, wipe or wand squeegees your sensor using a small, flat-edged paddle wrapped in a lint-free tissue. The tissue is treated with cleaning fluid and will handle just about anything, but using it requires the most care. Again, start at one side of the sensor and drag across, applying no more pressure than you would with a fountain pen. Optionally, you can then twist the swab 180 degrees and drag the clean side back across. As with any fluid, check with the manufacturer and make sure you have the right one for your camera. Also, make sure your paddle width matches your sensor size [sources: Chriss; Kelly; McHugh; Stern].
Other tools include sensor stain removal solution, sensor brush washers and brush-cleaning devices, but shutterbugs disagree regarding their usefulness and value, especially given their often steep price tags [sources: Breen; Chriss].
Now that you've swabbed the sensor, you can look at your lenses.