Sensor Cleaning Tutorial

August 28, 2010

Sensor Cleaning for Interchangeable Lens Cameras

It would be nice if camera bodies with interchangeable lenses sealed themselves during lens changes. Since they do not yet do this, there is always some dust or fibers which may sneak into the camera body during a lens change. The dust and fibers are then attracted to your sensor like a magnet because of the charge the sensor carries when it captures light. Dust which is not on the focal plane is usually not noticeable in photographs. So for instance a little dust on the end of your lens or dust in the camera body but not on the sensor will not be noticeable. However as soon as that dust or fiber sticks to your sensor then it will for sure show up on your photos as a dark spot.

This is a solved problem right?

The short answer is no. Many new cameras incorporate either a system to shake the sensor or to electrically push the dust off the sensor. The dust and fibers however are still in your camera body where they can re-attach at a later time.

How do I know if I have dust on the sensor?

You might already know you do have dust but if you want to find out for sure then take a photo of the clear blue sky. Then download the photo and zoom in to 50-100%. If you see dark spots where there should be none, then you have dust on your sensor.

What do I need to do now?

These instructions are specific to the Canon 5D Mark II but can be used on any DSLR or even any camera with an interchangeable lens. However you will need to read your cameras manual to find out how to put it in “cleaning mode” and follow the instructions for that mode. Make sure your battery is fully charged before doing this.

What tools do I need?

You will need at least three things and a few more optional items. The three mandatory items are:
1) A good blower
I like the Giotto Rocket Air Blower which you can pick up for about $15 including shipping. Note: do not use canned air as it has propellant which can leave residue. Also be wary of CO2 as some canisters have lubricant.

2) Photographic Solutions Sensor Swabs for your sensor size. This is the most expensive part at $35-40 per 12-pack.

3) Eclipse Optic Cleaning System Cleaning Fluid Note: This stuff is extremely flammable so you can only buy it in person in the store. If you don’t live in New York then you’ll have to find it at a local camera store. One bottle lasts a long time.

4) Optional: Sensor scope or magnifying loupe. These can get pricey and this one is $75. It does help in visualizing the problem though so you know where to concentrate the blower.

A Primer on sensors

It does not matter if you have a CCD or a CMOS sensor. The sensor always has a protective glass over it and it is this glass that you will be cleaning. Canon incorporates a low-pass filter in this as well to remove infrared light. Other manufacturers don’t do this. However the cleaning method remains the same regardless. While the glass is not delicate, it can be scratched so that is why care needs to be taken to prevent contamination anytime you will be physically contacting the sensor glass. Since it rests on the focal plane, any markings will be visible. If your sensor glass is damaged already, it is possible to repair although it is expensive. Contact the service department for your specific manufacturer to find out your options.

Let’s get started already!

The first thing I will say about this process is that it is best done in a clean room. If you take your camera to the manufacturers service center then this is what they do. Since most people I know don’t own clean rooms then a closed off room will have to do. If you have an air filter, turn it on high for about an hour ahead of time and then turn it off right before to let the air calm and the dust settle. If you have pets, kick them out. The last thing you need is your dog wagging his tail and some fur flying into your camera body.

1) Detach your lens and cap the end and temporarily put your body cap on the camera. Then put your camera in “Cleaning Mode”. Note: This is different from “clean the sensor now”. Like I mentioned before, every camera is different but to see how to do it for the Canon 5D Mark II just watch the video below. Lastly take off the body cap. You should notice that the mirror is now out of the way (if your camera has a mirror).

2) Grab your blower and proceed with blowing any dust and fibers out of the camera body. It is possible that you can clean the sensor only using the blower but if you cannot, it is still a good step to include. Blow as much out as you can while being careful not to touch the blower tip to anything in the camera including the sensor or the mirror.

3) Take one sensor swab and the sensor fluid and place it next to the camera. Now carefully open the sensor swab making sure not to touch the end with the swab on it. Apply a drop of liquid on each side of the sensor swab. Now firmly but gently swipe the swab from the left to the right of the sensor glass. Then make one swipe from the right to the left using the clean side of the swab. Now the swab is used and cannot be used again so just put it down anywhere. Once you put the body cap or your lens back on then you can take your camera out of “cleaning mode”.

Time to test the results

Place a wide angle lens on the camera if you have one and go outside. Aim at a clear blue sky up at about 75 degrees and opposite from the sun. Take several photos at the widest angle and then download them and look at them between 50-100%. You should not notice any dust but if you do you can repeat the steps. Sometimes just using the blower again can fix the problem.


Use your newly cleaned camera often. It may get dirty again but you now know how to clean it. This should lead to a much more enjoyable experience. If you end up with an impossibly to clean sensor then you might want to take it to the manufacturers service center.