"CCD Image Sensor Cleaning"

It is inevitable that at some point the image sensor of any dSLR camera will need to be cleaned. I had been putting this task off for a while, partly because it is such a frustrating exercise, and partly because I just don't have the ideal tools or environment to work in anymore. Alas, the day has come, I've decided to just get down to it and get it over and done with.

My camera has a full frame CCD type image sensor, without the anti-dust provisions more recent models have (i.e., sensor vibration, sensor coatings, dust-delete data, etc.). I often change lenses, and I even took it on expedition to Ecuador and the Galapagos Islands. In short, it has been put to test and was finally showing signs of enough accumulated dust to have obvious adverse affects on image quality.

I started out by checking out just how bad things were - that is, by taking a control shot before doing any cleaning steps. And, with no surprise, I found there was more than just dust all over the sensor.

Before Cleaning

In my first attempt I tried to simply brush the dust away, using a synthetic brush electrostatically charged with compressed air. The logic here was that the dust would preferentially stick to the brush. I should have known better, as I've tried this before and found it to make things worse!

After Brushing

Apparently I didn't remember my lesson right away, as I continued on with another two rounds of brushing - first switching to a blower-brush, then back to the synthetic brush once again.

Blower Brush
Second Brushing

At this point I had made it so much worse that I completely threw caution to the wind and tried to blow the dust off directly from a can of compressed air. This did absolutely nothing, with the risk of welding dust to the sensor surface.

Canned Air

Now it was time to resort to the one method that has worked at all - wet cleaning. In this method a lint-free swab is wetted with filtered methanol and swiped across the surface of the sensor, once in each direction. After one use the swab is to be discarded, and it generally takes a number of attempts to get all the dust off. After the first swiping there was a marked improvement, though there was still a lot of left over debris to clean from my earlier failed attempts. With each consecutive swiping the battle turned as the dust receded; but it wouldn't be over quickly.

After using all four of the prepared swabs I had available the sensor was looking much better, but still had some stubborn specks.

1st Swabbing
2nd Swabbing
3rd Swabbing
4th Swabbing

With a good amount of reservation, I took a chance at reusing a few of the swabs a second time.

1st swab reused
2nd swab reused
3rd swab reused

By the time I got to reusing the third swab it seemed that I might just be pushing stuff around on the surface, so I decided to cut up some PecPad sheets to make my own swabs. I still had plenty of the cleaning fluid left, so if this worked I would effectively have dramatically increased my potential stock of swabs (which I hoped I wouldn't need of course).

My first homemade swab appeared to work well enough, though it left some strands of lint behind. A second attempt, paying attention to carefully construct the swab, did a very nice job of cleaning up the remainder of the debris.

1st homemade swab
2nd homemade swab

It still is not perfectly clean, but it is comparatively much, much better. What little is left on the sensor is not likely to be perceptible in most any images shot under typical conditions. Aside from clear areas of images shot with very small apertures I don't expect to find any specks lurking in my photos. Of course, some day it will get dusty and need the process started all over again - but that's just part of maintaining a dSLR.

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