Digital photography horrors

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If you're shooting with a digital SLR and start to notice dark specks appearing in your photos, don't get all short of breath: this is not caused by ectoplasm seeping in from the spirit world. It's just dust. When you change lenses on an SLR, dust can get inside the camera and settle on the sensor, darkening little spots in the pictures you take.

1. Buy a self-cleaning SLR.

Dust specks on the sensor cause dark spots like the ones marring the sky in the photo on the left. You can see the spots close-up on the right. Click to enlarge

Olympus's E1 and Evolt E-300 SLRs have what the company calls a Supersonic Wave Filter built in. Every time you turn the camera on or activate the filter, it vibrates the sensor to shake dust off. The dust is then collected on adhesive strips along the sides of the sensor. In our experience, this system works pretty well. It's a pity other manufacturers don't offer something similar.

2. Clean your camera with care. If you don't have an Olympus SLR (or even if you do but are in a very dusty environment), sooner or later you'll have to clean the sensor. If you're nervous about doing it yourself, you can send it to the manufacturer for a professional cleaning. However, that's not a very practical or affordable way to handle the situation every time a new little spot shows up. Although you should take the utmost care, the best solution is probably to clean the dust out yourself.

Most sensors are covered with protective glass, and if you scratch or damage it, there's a good chance the manufacturer's warranty will not pick up the tab for repairs. So don't be cavalier about what you stick inside the camera. Never blow compressed air into your camera. It uses propellants that can leave a residue.

Use products that are made specifically for sensor cleaning. A number of companies make them, including Photographic Solutions and Visible Dust. Kinetronics' Speck Grabber is useful for getting at particular bits of debris, since it has a little light built in. And Kodak sells its own sensor-cleaning kit and provides detailed instructions on how to clean its cameras' sensors.

When you're ready to clean the sensor, put the camera into sensor-cleaning mode so that the sensor is exposed (check the manual about how to do this with your particular model) and remove the lens. You can use a bulb blower to blow dust off the sensor; just make sure you hold the camera up so that the dust falls out instead of settling inside again. Follow the instructions of the cleaning product you've chosen. Usually this will involve carefully swabbing the surface of the protective glass over the sensor.

To make sure you've eradicated all debris, you can take a picture of a blank wall or piece of paper. Look at it at full size on a computer monitor and see if you can detect any remaining specks.