Sense the dust
12 Oct 2004<img src=”https://www.phrixus.co.uk/images/blog/sensor.jpg” class=”image” align=”left”width=”240” height=”180” alt=”Canon EOS 10D CMOS Sensor” />This is the CMOS sensor from inside a Canon EOS 10D. It is the very source of all the image information that the camera captures and must therefore be kept clear of any contaminants. There are 6.5 Million individual pixels crammed into the 22.7 x 15.1 mm area. Just a tiny spec of dust on the sensor turns into a monster dark spot on an image when viewed. I have just had the pleasure of rubbing my CMOS sensor to remove this and I really hope it wasn’t the wrong way! This is not an issue that really concerns film cameras as each time a photo is taken, the film moves along and in a worst case scenario, only one frame is likely to be ruined by a contaminant. As the sensor of a digital camera does not move, any debris that settles, has to be removed. For me, the cleaning process started out as a methodical ‘follow the instructions’ then turned into a bit of a Brehaut special with the photographic equivalent of a Brillo pad being used to clean the surface of the sensor. To get an idea of why my blood pressure was higher at the end of this operation than at the beginning… read on!!
The instruction manual clearly states that only a very small rubber air blower should be used to clean the sensor, under no circumstances should you use a brush, cloth or canned air as these may each damage the sensor. As it turned out none of these or worse appears to have done much harm to mine but I will know more over the next few weeks! Looking into the body, I could just about get my eyes to focus on the specs of dust that were visible on the sensor. I took my trusty rubber blower and started squeezing and aiming the tiny jets of air at the sensor. A few minutes of this and the dust was still there. More pressure was needed and I calculated that if I held an air can away from the camera, it would probably be ok so I tried that. This operation went on for a few minutes aswell and ended with the nozzle heading into the camera body and getting very cold in my hand. Another failure, the dust was still where it had started. Apparently, slightly more aggressive measures were needed so I reached for my ultra fine weave lens cloth and very lightly pulled it across the sensor. Yet again, the dust was still there. By now I am thinking that this is slightly more than your average surface dust and something extreme must be required. All logic apparently gone, I gave a good old breath onto the sensor to fog it up a bit and used a cotton bud to wipe the dust off. The operation actually involved a bit of rubbing followed by more rubbing to remove the smear marks! All in all… it ended up looking as good as before less the dust. I will try taking some pictures in the near future and see if I have caused any lasting damage. As Canon have just released the EOD 20D, perhaps a replacement would not be so bad!
<img src=”https://www.phrixus.co.uk/images/blog/side2.JPG” width=”174” height=”217” class=”image” align=”right”alt=”EOS 10D on back” />
Investigation into the cause of this problem has shown that perhaps my storage technique is partially to blame. I own a LowePro Orion Trekker rucksack that is spilt horizontally inside which my camera fits tightly with the lens facing up towards the top. This has proved to be the easiest way to put the camera in and out. What I hadn’t realized was that with the camera stored in this way all the time, the dust would follow the laws set out by Newton and fall directly down onto the sensor in the back of the camera. It is apparent that my plan for buying a new bag is now justified. 
The next bag will have a design in which the bag is split vertically to get to the camera. This will also allow me to get a magazine inside which I cannot currently do and should be considered vital when travelling. In the meantime, I have turned the camera over so that the lens faces down. The bag pictured here is a LowePro Dryzone bag. These can actually be thrown into water and the gear inside will stay dry. As my camera spends quite some time at sea, perhaps a model like this should be considered.
