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Dust Problems with Digital SLR Cameras

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  • Dust Problems with Digital SLR Cameras

    Cleaning the Sensor on a Digital SLR
    NB: No liability accepted for the application of this advice. Any cleaning is performed at your own risk.

    After a while, your digital SLR may begin to produce pictures with a degraded image quality caused by dust entering the camera when the lens has been removed. Many digital SLR cameras now employ some kind of automatic or manually triggered dust-reduction system, of which the Olympus SSWF (Super-Sonic Wave Filter) and Nikon’s IDRS (Integrated Dust Reduction System) generally perform the best in independent tests – although neither are actually completely effective. There will one day come a point where the sensor system needs a clean and having your camera cleaned professionally once in a while is a good idea if it gets heavy use.

    Despite what is frequently said, it isn’t normally the sensor that attracts dust, pollen and hairs – it’s the anti-aliasing and IR block filter that sits just above it. That’s what needs cleaning more than anything else and you can easily do this yourself. Under no circumstances should the filter or other parts of the sensor system be touched with the fingers or given direct contact from anything which could create scratches. You need a “blower bulb” and a “sensor brush” (and I would suggest a can of compressed air, although you won’t be squirting this inside the camera).

    The blower bulb of choice for most people is a “Giotto Rocket” (which comes in several variants). It directs a stream of air at the sensor filter and a few puffs of the bulb with the end held close to the filter will dislodge most dust. Don’t buy a cheap blower – they sometimes have a silicone lubricant in the bulb which can create more dust than it removes. Keep it clean and dust-free in a zip-lock bag when not in use.

    A sensor brush has extremely fine, soft bristles that have no coating. For most types you “charge” them electrostatically before use so that the bristles have a stronger attraction for the dust than the filter and then “discharge” them to get the dust off the bristles. That’s done either with a blower bulb or (better still) with a short blast of compressed air from a can before and after use. Don’t buy a blower/brush combination of the kind sold for about $5 in photographic shops for lens dusting. You can expect to pay $25 - $50 for a decent one.

    Brushes come in all widths for different size sensors but I would actually recommend getting one that’s a bit smaller than your sensor. That means you’ll have to do several “passes” across the filter, but a smaller brush means it’s less likely that you accidentally touch the walls of the chamber or the mounting frame that holds the sensor. Those areas may have residues of a fine oily lubricant on them which you don’t want to contaminate the brush or transfer to the filter.

    Charge and discharge after each pass over the filter and remember to discharge before storing it in a dustproof box with an airtight lid. Decent brushes will come with a suitable storage box. I put mine in a zip-lock back as well, for further protection. Once you have a sensor brush, use it only for that purpose. Never use it on your lenses or anything else.

    There are also higher tech (and more expensive) products such as the “Brushoff” by Photographic Solutions. All of these items are available here (and you may find better prices by shopping around):

    http://www.micro-tools.com/store/Sea...tegoryCode=119

    There are even more sophisticated battery powered brushes which charge themselves via an electric motor and have lights to theoretically highlight any deposits on the filter, like those from the “Arctic Butterfly” range by Visible Dust. But you’re then getting to $150 or more and – frankly – they aren’t worth the extra money in my opinion. Most of the dust you will be removing won’t be visible to the naked eye anyway, even with the illumination.

    None of these will remove dust which is stuck to the sensor filter via lubricant traces or sticky deposits such as some pollens. For that you need to wet clean with a swab, such as “Sensor Swabs”, also from Photographic Solutions, or other similar products:

    http://www.micro-tools.com/store/Sea...tegoryCode=118

    My advice would be that this kind of cleaning is best left to a professional. If you don’t know what you’re doing it’s easy to leave streaks by using the incorrect amount of fluid, the wrong angle of the swab or insufficient pressure. Although Photo Solutions (and others) commendably offer a guarantee that your sensor won’t be harmed, the guarantee applies to proper use of the cleaning fluids and the materials of construction of the swabs. The sensor filter itself is normally pretty hard but has a special tin oxide coating which can be scratched by grit. If you've been using the camera around rocks and fossils, then it's pretty likely you will have gritty dust rather than regular household dust. If you do try this, it’s essential to remove any loose dust first and you should always “sweep” rather than “rub” (and definitely not use a “to and fro” or “round and round” action.) Otherwise, the guarantee won’t apply.

    There are also adhesive cleaning strips available from Dust-Aid, which you just press on and lift off the sensor filter a couple of times:

    http://www.dust-aid.com/08cleaningstrips.html

    I’ve never used them, but the advantage seems to be that that they remove more deposits than blowing and brushing and - although perhaps not as good as a wet clean – have no risk of scratching.
    I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.
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