Simple (dry) sensor cleaning

It takes a steady, strong hand to use a bulb blower so that you get enough air blown onto the CMOS to remove dust particles, but avoid getting the tip too deep into the camera where it risks touching the sensor. (Taken with an EOS 5D using an EF 100mm f/2.8L Macro lens at ISO 200, 1/160 second, f/16.)

By far the simplest way to clean a sensor marred by dust spots, and your first course of action, is to use a bulb blower (see 10-7). This is known as a dry method of cleaning a camera. Bulb blowers, which are available at any camera store, allow you to force a strong stream of air into your camera to blow the dust particles off of your CMOS.

Using a bulb blower before every significant use of the camera isn’t a bad idea. It will help keep dust particles off the sensor, and hopefully remove as many of them as possible so that they don’t adhere after sitting for a long time.

It only takes a minute to perform a simple sensor cleaning, but you must ensure a few things are in place before you do it:

  • Find a clean, breezeless, dust-free, and dry area in which to work.
  • Make sure your camera’s battery is fully charged, or use your AC connector for the camera. If your camera were to lose power during the sensor-cleaning process, the mirror could come down and strike the blower, which would be a serious problem requiring professional assistance.
  • You can hold the camera with the opening pointed down while you blow, but be careful not to inadvertently thrust the blower point into the camera too deeply during the motion of blowing it. You can also lay the camera on its back or mount it on a tripod.
  • Ensure your bulb blower is clean and free of dust. You don’t want to blow dust onto your sensor!
  • Remove any lens you have on the camera. If you want to keep your camera body closed unt you’re ready to use the bulb blower, use your camera body cap — it will be much easier to remove and replace during the sensor-cleaning process.

You will need to familiarize yourself with your camera’s menu controls for the sensor-cleaning process. Typically, here is how it works for most Canon cameras (note that it may vary from model to model and you should consult your user manual for camera-specific operations):

  1. Using the camera’s Setup menu, select Sensor Cleaning from the list on your LCD.
  2. Select Clean Now, then OK, and then Set. Doing so causes the mirror to lock in an upright position, exposing the CMOS image sensor. Your camera is now ready to have the sensor cleaned with the bulb blower.
  3. Place or hold the camera stably and remove the body cap. Once removed, you will see that the mirror is up and the sensor will be visible at the back of the open space.
  4. Carefully hold the bulb blower so that its tip is inserted into the camera body, but keep the end at least an inch above the surface of the sensor (see figure 10-7). When you press the bulb to blow air on the sensor, the tip will move; you do not want to risk having it scratch the sensor. Get it close enough to do the job, but far-enough away to be used safely.
  5. Squeeze the blower with quick, strong bursts. As you squeeze, air blows onto the sensor. You can move the tip back and forth above the sensor to ensure full coverage of the sensor, but there’s no need to move it up and down. About five or ten strong squeezes should be sufficient to remove any loose dust that can be removed by this method.
  6. After you have finished, replace the cap on the camera and turn it off. You will hear the mirror drop into its normal resting position. You have now completed the sensor cleaning, and you should take some test images to see if your cleaning has succeeded in removing the dust particles.

If after cleaning you still see dust spots on your CMOS, you may have noticed that at the very least some of them have moved around. This is actually a good sign, meaning that even though they didn’t come off in your first attempt, they have not adhered to the surface. Following these steps one more time may do the trick to get the sensor clean.


Do not touch the sensor with the blower, your finger, or anything else.


Most cameras will begin to beep if they are running low on power during the cleaning process


Never remove a battery or disconnect the power during sensor cleaning.


Never, under any circumstances, use canned air to blow a sensor. It uses a chemical to propel the air that can create a freezing residue and film, permanently damaging your sensor.

Category: Camera care

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