Sensor Cleaning

I was asked recently if I clean my camera’s sensor, and if so, how.

I shoot using a full frame 35mm format camera. The size of the sensor means not only do I get images superior to anything I could get using film (in fact that rival on a quality basis – discounting depth of field – images I got shooting 6×6 cm film) but it is an extraordinarily efficient dust collector.

So the answer is “yes”, I clean my sensor.

Technically I am cleaning the low pass (anti-aliasing) filer that sits on top of the sensor. I can only imagine what my images would look like if this was not in place (scary sharp is the short answer), but it is what it is. It’s there. As a slight aside, this is a big advantage that medium format cameras have (and the Leica M9) – they don’t use them. I wonder if they don’t have significant problems with moire patterns, then why are all the 35mm DSLR manufacturers so hung up on having them?

Anyway, back on topic.

Yes, my camera has a “dust reduction system” – it uses the in-body stabilizing system to shake the sensor, but this is not enough. It needs to be cleaned.

First of all, as with any maintenance, I believe in only doing it when needed. When I start seeing dust spots (most apparent at small apertures – f/16 and on) in bright areas such as the sky, I know it’s time to clean.

The first thing you’ll need is some sort of a lighted loop. I use the one from Delkin Devices, but any will do. You just need something to be able to view the filter and see if it’s dirty and, if it is, the effectiveness of your cleaning efforts.

I’ll be honest with you: cleaning the low pass filter makes me nervous.

So I start out with the least effective but potentially least (potentially) damaging solution: I take a rocket blower and blow it out. I understand that this may be doing nothing more than moving the dust around, but I start here.

If there is still crud there (probable), then I use the Arctic Buttefly to try and remove it. Yes, it is over-priced. But it is effective. And it does not rely on putting anything on that filter, which is a big plus in my book. Make sure you follow the directions. I always spin the brush after each attempt to knock the dust off and to recharge it, and I make sure that i also swipe the rest of the mirror box (there is a brush for that too) to try and remove as much dust as possible.

If some still remains, it’s time to bite the bullet and use a wet solution. This is always the last solution tried – it is potentially the one that will get you into trouble. I use Sensor Swabs. I put 3 or 4 drops on 1 side, make 1 pass in one direction, use the other (dry) side in the opposite direction to wipe off any residue, and then throw the thing away. 1 wet pass on 1 side, 1 drying pass on the other. That’s it.

I have tried using multiple passes and all it does is make a mess. You’ll end up laying the dust back down (only wet this time, so it sticks extra well).

I did not say this process is cheap. It’s not. But there really is no alternative.

A few preventive tips:

  • the obvious one is to be careful when you change lenses. You will be better off minimizing opportunity to get dust into your camera in the first place
  • be careful where you store lens end caps and camera body caps. Putting them in your pocket is not a good idea as lint can get on them, and then be transferred into your camera
  • make sure the body end of your lens is clean. I believe this is how most dust gets into your camera

Again, I clean only when necessary, but I do clean. You probably should too. But please, be careful. Wet methods can leave a residue (a smear) on your filter which can be hard to get off. And there is always the possibility that you can scratch it.


This entry was posted in Technique.