We all know that when you change lenses, dust can enter the camera and be deposited on the filter in front of the sensor. Dust can even be generated inside the camera by the friction between moving parts.

Whatever the cause, the result is the same: blotches in the same place on every frame. When you consider that the imaging sensor inside your Canon DSLR is packed with millions of receptors, yet isn’t much bigger than a postage stamp, you can imagine how much detail a minute piece of dust can potentially obscure in an image.

Sensor dust is most noticeable in areas of smooth, pale tones such as skies, particularly if you’re shooting with narrow apertures, and it becomes particularly obvious if you use a narrow aperture and slow shutter speed during a panning shot.

Bear in mind that it’s only once you’ve taken a picture and you’re looking at it on the rear LCD or on a computer that you’ll spot sensor dust. If you notice other specks when you’re looking through the viewfinder, it’s either the viewfinder window or the mirror inside the camera that require a quick blast from a rubber bulb blower.

The Integrated Cleaning System inside your Canon DSLR does a fine job of vibrating most of the offending particles away from the sensor, but it isn’t perfect. Image-editing programs such as Photoshop make removing any shake-resistant spots relatively simple, but it’s better to remove the dust from the sensor directly.

If you’ve got the right tools and lots of patience you can have a go yourself; although bear in mind that you’ll void your warranty, and replacing a scratched sensor doesn’t come cheap! If in any doubt, leave it to a Canon-approved service centre.

What you’ll need to clean the sensor in your EOS camera

A whole industry has built up around camera care products, with sensor cleaning devices in particular taking many different formats. But which items do you really need?

We’d recommend that a minimum on-the- road cleaning kit comprises a bulb blower, brush and microfibre cloth. You can add a set of wet/dry sensor swabs and a sensor loupe if you’re confident of removing dust manually, although with the EOS Integrated Cleaning System doing a genuinely fine job of removing dust particles automatically, this should be a relatively rare requirement.

It’s also a good idea to keep a pack of lint-free Pec-Pads or lens tissues in your camera bag to help remove marks from lens mounts, buttons and LCD screens.

Warning: dust-spotting your Canon camera’s sensor requires a gentle touch and the right equipment.

How to clean the sensor in your EOS camera

Step 1: Try auto cleaning
Make sure the camera battery is fully charged, then select the ‘Sensor cleaning’ option in the second Setup (yellow) menu. Choose the automatic option to start with.

Step 2: Switch to manual
If dust persists, return to the sensor cleaning menu and select the manual option. This locks the mirror up and opens the shutter. Remove the lens to get access to the sensor.

Step 3: Use a blower
First, use a manual air blower to dislodge any particles – face the camera down so that these fall out of the body. Avoid using a compressed air can. Now take a test shot.

Step 4: Start dry cleaning
If dust remains, charge a sensor brush for ten seconds and carefully drag this over the sensor. If dirt is stuck to the sensor, do a wet clean with a swab and sensor cleaning fluid.

After you’ve finished your Canon sensor cleaning…

When the sensor has been cleaned – either automatically by the camera or manually, by you – take a test shot to check that all is clear. Switch the camera to Av mode, and set the smallest aperture available on the lens.

Photograph a bright, clean area – a piece of white paper is ideal – with the lens manually focused at a close distance. Upload this shot to your imaging software and apply Auto Levels or the equivalent to show up any specks.

The bottom of the image actually represents the top of the sensor, so flip the image vertically prior to cleaning your sensor to find out where on the sensor the dust lies. A sensor loupe – a device incorporating a magnifying lens and lights that fits over the lens mount – is also a great aid here.
 

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Camera Tips

No matter how careful you are, dust always seems to end up in the inner workings of your D-SLR. This is most problematic in landscape photography as shooting at small apertures such as f/22 aren’t as forgiving as shooting at, say, f/4. Often the first time you’ll notice these marks appearing on your shots is when you open them up in Photoshop. Most imperfections can be removed using Photoshop’s 3 main dust removal tools, each of which can be used to quickly fix different areas and blemish types. Find out how to use the Spot Healing Brush, the Healing Brush and the Clone tool.