For the last two years, I have been deluged with questions concerning the issue of methods for field cleaning sensors in digital SLR’s. Maintaining a dust-free environment inside the camera and how to deal with the dust that does (inevitably) find its way onto the sensor has gotten to be as an important of an issue during my workshops as white balance, composition and metering. Sensor cleaning tools and technology is currently lagging behind the rapid growth of digital SLRs in the marketplace. Even today, Canon’s website recommends that if blowing the dust off with a squeeze bulb fails then the camera should be taken to a reputable dealer for cleaning. I don’t know about the rest of you, but dust is a daily problem and the nearest dealer (of any reputation) is often hundreds of miles away.

(NOTE: I am not a proponent of using a jet of clean air to remove dust from sensor surfaces. [NEVER use canned air.] One is never assured that the dust is blown completely out of the sensor chamber. The chances are too great that the dust particles have stuck to another surface within the chamber and will eventually find their way back to the static charged sensor surface.)

    To resolve the field cleaning needs, special cleaning brushes have come on the market and this technology now dominates the choices available to clean sensors safely and effectively. For the most part, field experience has shown these specialized brushes to be effective in removing dust from sensor surfaces. There are also various types of cleaning swabs that are now making their way to the marketplace but it is the brush technology that I wish to address here.

    Almost all of the brushes on the market today that are “designed” to clean digital sensors have two factors in common. The first is that they are expensive. Prices are currently running between $50-$125. The second is that they are all made with synthetic bristles (usually a form of nylon) which, to an old engineer and chemist like myself, puts them in the same category as high quality artist brushes. It is important to note that the bristles are synthetic rather than hair-based due to their ability to hold a static charge similar to the way a toy balloon holds a static charge on its surface when rubbed. It is the static charge as well as the bristles that remove the dust from sensors.

    For the last two years I have carried a set of brushes, purchased from my local art supply store, and used them to clean participant’s cameras during workshops. After performing hundreds of cleanings on dozens of different makes and models, I have yet to run into a dust situation that could not be cleaned by these $7 brushes. (Note: I still need/use a squeeze bulb to blow the dust particles off of the bristles which also helps them to maintain a static charge.)

Where to Purchase: Any good quality art supply store that sells brushes individually and not as a set. Depending on brand, prices can run $5-$12.  I carry two brushes with me. One is strictly used on the sensor (a non-grease area) and the other is used for cleaning the mirror area.

Brush type: Get one that is labeled as “synthetic” or “nylon”. Do not purchase a horse-hair, camel-hair or any other type-hair brush as hair will not hold a static charge.

Brush Size:  For full framed sensors use a 1/2″ or size 12 brush; for smaller sensors use a brush that is 1/4″ – 3/8″. The idea here is that you do not want the brush to be the same wide as the sensor. A smaller width allows you to lay the brush on the sensor without touching the sides and to give you the ability to clean in the corners.

Bristle Length: A brush that has short bristles is too stiff to clean sensors and increases the chance of scratching the surface. For a 1/2″ wide brush a bristle length of 3/4″-1″ is ideal. For narrower brushes don’t go less than 5/8″. These lengths create a softer feel to the bristles and provides a greater surface area to pick up dust.

When You Get Them Home: As you don’t know where the brush has been or who has touched it before you, soak the brush in isopropyl alcohol (rubbing alcohol) for about 10 minutes to get rid any oil residue from fingers or the manufacturing process. This is also a good way to keep the brush clean on an ongoing basis. FROM THIS POINT ON DO NOT TOUCH THE BRISTLES! Let the brush air dry and store in a dust-proof container. I use a traveler’s toothbrush case. It hold two brushes and is light weight. Note: As these cases are shorter than the average artist’s brush I simply cut off part of the handle.

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