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DUST, DUST AND MORE DUST
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.
For more information on Mark's
Wildlight safaris and photo trips send your request to:
info@wildlightnaturephotography.com
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