G Dan Mitchell Photography

I just read a forum thread on dealing with “sensor gunk” on DSLR cameras. I posted a response and thought I’d share it here as well:

When I got my first DSLR I was very upset if I got any dust in a shot. I was also very paranoid about cleaning the sensor*, having read two many posts about how you could damage the sensor. Now that I’ve used DSLRs for a few years I’ve gotten over it and life is much, much easier.

Here is a summary of my approach** to dealing with sensor junk…

Rule #1: I don’t worry too much about a small amount of dust. I rarely can get a sensor clean enough to get perfect, dust-free shots at smaller apertures, and when I do the dust will soon return. Rather than worry too much I’ve found that it is easy to quickly fix most small spots in post-processing. Using one or the other tool, I can usually deal with most dust spots in a matter of a few seconds in Photoshop.

Rule #2: When the dust gets to the point that dealing with it in post is no longer efficient, I try the easiest thing first. When I notice a larger than usual speck or when the build-up gets to the point that post-processing cleanup is either taking too long or not working right, I use a blower to try to clean out the worst of the stuff. More often than not this is enough and I can go back to relying on rule #1. Point the tip of a good blower bulb into the chamber but keep the tip itself just outside. As you blow a few dozen puffs into the chamber and toward the sensor change the angle of the bulb to ensure that you get full coverage. It is probably best to hold the camera with the open chamber facing down.

Rule #3: Sometimes rules #1 and #2 aren’t enough. At this point I try a static charged sensor brush, being _very_ careful to avoid letting the brush touch anything but the sensor itself. Yes, the brush can pick up other stuff in the chamber, and I have learned from experience to avoid this. However, most often the brush is all I need to use to get my sensor back to “sufficiently clean” status. With care and a bit of luck the brush method can sometimes get the sensor absolutely clean. The whole task takes me just a minute or two. I rarely have to escalate past the “blower and brush” technique – probably not more than once or twice a year – and in nearly all cases I can get the sensor glass very clean this way.

Rule #4: On rare occasions rule #3 fails, too. If the contamination is adhering too firmly to the sensor surface I resort to wet cleaning with Eclipse fluid and PecPads. I can rarely get it right in one attempt, so I plan on having to work at this a bit. Be very cautious to not use pressure or “scrub” the sensor glass. Let the fluid loosen and/or dissolve the material and gently wipe it off with the pad attached to the “spatula” tool. Read the instructions for this cleaning method very carefully before attempting it. It isn’t terribly difficult but there are a few ways you can go wrong including: pressing too hard and damaging the coating on the sensor glass, transferring lubricants to the sensor from other parts of the camera chamber, leaving streaks on the sensor. Eventually I get a reasonably clean sensor with no streaks.

Rule #5: On very rare occasions a combination of methods is required. Often the wet cleaning works well for me but leaves a few spots of dust on the sensor. For this reason I frequently follow the wet cleaning with a quick once-over with the static charged brush.

From all of this, it might sound like I’m sensor-obsessed. I’m not. Remember rule #1 is the one I follow most. I usually go months between real sensor cleaning sessions.

*I’ll anticipate that someone might feel obligated to write, “You aren’t really cleaning the SENSOR! You are cleaning the glass cover over the sensor, you nitwit!” Yes, I know that. It is just easier to refer to the whole assembly as “the sensor.” :-)

UPDATE: Since I originally wrote this I acquired a Canon EOS 5D2 body which includes an automatic dust reduction system that vibrates the sensor when the camera is turned on and off. I can report that this method seems to be very effective. I’ve had the camera for 9 or 10 months now, and I have yet to need to clean the sensor at all! I occasionally spot a small bit of dust or two when I shoot at small apertures, but the spots seem to disappear of their own accord  within a few shots.

UPDATE: In late 2008 I purchased a Canon 5D2, which has a dust-reduction system. It “vibrates” the sensor (as I understand it) when the camera is turned on or off, thereby dislodging dust from the sensor (AA glass) on a regular basis. I did not have high hopes for this system when I got the camera, based both on my understanding of how it works and on some initial published reports that were not encouraging. After using it for a year, my opinion has changed almost completely. I find that the “dust shaker” system on this camera is actually very effective. I have yet to need to do a manual sensor cleaning – although I used to do this more or less monthly with my older 5D. When a dust speck does show up occasionally, it usually disappears a few frames later after I switch the camera off/on.

**Disclaimer: This report describes what I do, but I am not any sort of certified expert on these things – as I wrote, this is “my approach.” I strongly urge you to seek out and learn from other official sources of information on sensor cleaning and related issues. The inside of your camera contains fragile and sensitive electronic and mechanical components and it is possible to cause damage while working there. You should read and carefully consider warnings from the manufacturer of your camera and any accessories and tools you use on it. If you are not convinced that you are competent to do this work on your camera, you can always take it to a professional. I do not claim that my methods are the best or most appropriate, nor that they meet the standards of the manufacturers of the camera equipment nor do I recommend that you use my methods in place of manufacturers’ official recommendations.

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G Dan Mitchell :: Oct.20.2007
Commentary, Equipment, Popular, Technique
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