Cleaning the Sensor on a DSLR
Saturday, May 13th, 2006
As many people with Digital Single Lens Reflex cameras know, the downside of changing lenses is the possibility (more like inevitability) of dust getting on both the mirror and the sensor inside the camera. The sensor is the large piece of silicon, either CCD or CMOS, that is covered with light sensitive transistors that capture the image. The mirror, which is part of the optical/mechanical configuration of any SLR allows the photographer to look through the viewfinder and see exactly through the lens. Dust on the mirror is a visual annoyance but does not get recorded on the image. Dust on the sensor can show up on the image.
To be totally accurate, the sensor itself is not fully exposed; it’s covered by a “low pass filter” that is actually what the dust is getting on. In more serious cases dust can get under the low pass filer and directly on the sensor. This is very bad news but also quite unusual.
One could call this a major design flaw of DSLRs but all brands except one suffer from it. Olympus EVOLT cameras have a filter between the shutter and the sensor that is charged so that dust will fall off of it. I’m not sure how well it works but it sounds like a step in the right direction.
All other DSLRs from Nikon, Canon and every other camera maker that makes cameras with interchangeable lenses suffers from this problem. I suppose one could buy any camera and just the right single lens and never take the lens off and not suffer from the problem, however, few cameras ship new without a bit of dust on their sensors so some dust might not even be from users opening up their cameras in high wind at the beach.
Tips: Before changing lenses turn the camera off and let it sit for a second so the charge on the sensor diminishes so as not to pull in more dust. Leaving the camera turned on and the sensor charged runs the risk of pulling in more dust.
Change lenses inside or in a protected place when possible.
Plan ahead and have the right lens on the camera before you leave for a shoot, the fewer changes the better.
How do you know you have a dirty sensor?
If you shoot Av (aperture priority or preferred) and have fast lenses and shoot with them wide open, you won’t notice a dirty sensor much if at all. However, as you stop down (reduce the size of the aperture) you will start to see the dust, if you have it.
Put any lens on your camera, set the camera to Av mode (aperture preferred) and stop down to f/16 or smaller.
Take a picture of a white wall or a white computer screen.
Look at the picture on your computer. If you see spots, you’ve got dust. Note, it’s useful to try to remember where the spots are so that as you clean you can see if you’re making any progress when you check again.
Here is an extreme example from flickr.
What to do?
The simplest thing to do is this (and Canon and Nikon recommend it):
1. Buy a Rocket Blower and have it on hand. It’s useful for other camera and lens cleaning chores as well.
2. Find a clean place in your house to work, as dust free as possible. No moving air in the room if possible.
3. Read your manual and learn how to change the mode of your camera so you can clean the sensor. On my Canon 20D there is a menu item called “Clean Sensor” that locks the mirror up automatically and leaves it like that until I turn the camera off. Remember to use a fully charged battery when you lock the mirror up for sensor cleaning.
4. Once the mirror is locked up, take the lens or the body cap off the camera, hold the camera with the opening facing down and use the Rocket Blower to blast some air inside onto the sensor. Do not touch the tip of the blower to any part of the camera. Be careful.
5. Put a lens back on the camera and turn the camera off. This will cause the mirror to fall back into place.
6. Test for dust again by turning the camera on, setting it to Av mode, stopping down, taking picture of white wall and looking at it. If you got rid of all the dust, you’re lucky. If not, did you get any dust off? Did anything change? If nothing changed it may be necessary to try another method.
Warning: do not use compressed air to clean any part of a camera, especially the inside. Generally compressed air has a liquid propellant that can come out with the air and you do not want this propellant on your sensor.
Charged Brushes
Two companies make special brushes for picking dust up off sensors: VisibleDust and Copperhill. I’ve tried the Copperhill brush and it pulled only the very loose dust off of my sensor, anything that was really sticking didn’t move at all with this method. However, this method is pretty safe, it would be hard to scratch the low pass filter covering the sensor with one of these brushes. Both of these methods use a clean brush that is slightly charged, either by blowing compressed air through the bristles or by brushing back and forth on a special piece of material. That charge is what is lifting and holding the dust onto the brush (hopefully). The downside of these brushes is that it’s possible to introduce more dust into the camera or simply move around the dust that’s in there.
Sensor Swabs and wet cleaning
Sensor swabs are plastic spatulas with lintless micro-fiber material attached to the end. You put a few drops of special optical cleaner on the end of the swab and drag it across the sensor to “mop up” dust. I bought both the swabs and cleaner from Filter Connection. The manufacturer is Photographic Solutions and they also sell it. For about four months I kept my sensor relatively clean with this method. The liquid evaporates immediately and leaves no residue behind. However, some dust and dirt may not respond to even this method.
Canon Service Centers
You can take your Canon DSLR camera to any of these service centers and they will clean the sensor at no charge. If there is damage to the sensor they will give you an estimate for a repair if the camera is out of warranty or you caused the problem.
If you don’t live close enough to drive to one, call the nearest one and ask about shipping the camera to them. Generally there is no charge for cleaning the sensor. There may be a small shipping charge to get the camera shipped back.
Canon has three US service centers:
Jamesburg, New Jersey: 732-521-7007
Elk Grove Village, Illinois: 847-364-0900
Irvine, California: 949-753-4200
Canon Service Center, Jamesburg, New Jersey
I’ve had my Canon 20D for about a year. I use only prime lenses (fixed focal length) so I change lenses often. In the early days, I left my camera on and violated all the rules for avoiding dust. I’ve used every method mentioned above and I’ve done a decent job of keeping my sensor reasonably clean but recently I noticed that each time I stopped down smaller than f/5.6 I was looking at a lot of dust on my images. I tried one last cleaning and knew I needed professional help.
I called Canon’s New Jersey Service center and spoke with Jamie, a very nice woman who runs the front desk. I told her my situation and she told me to come down and they’d take good care of me. She was empathetic although she did warn me that if they found problems beyond dirt it might lead to a repair that would cost money and mean leaving the camera with them.
For those of you who live near enough, here’s where Canon’s New Jersey Service Center is.
Get off the New Jersey Turnpike at Exit 8A. Bear right off the ramp. Take a right on Cranbury/South River Rd. Go a few miles, then look for Ridge Rd. / Rhode Hall Rd. Turn left on Ridge and Canon will be on your right. Turn right into the parking lot and then left into a smaller customer service parking lot. The service center is right in front of you.
I drove down, waited an hour while they cleaned about ten cameras including mine. Jamie told me to come back whenever I needed a cleaning done, monthly if I wanted. Some New York pros have it done monthly to multiple bodies, no charge.
I’ll use a blower and be careful from now on but knowing that Canon offers a service like this is reassuring to me.
Note: A number of the people in the waiting area thought I was nuts to have driven down from Connecticut and told me that there were a few closer Canon authorized places to have sensors cleaned. Jamie gave me a list of them and I called one in Connecticut. If the camera is within its one year warranty the cleaning is free and takes ten days. It the camera is outside the warranty the cost is $165. I think I’ll drive to New Jersey and have Canon do it.
More Resources
Cleaning Camera Sensors
Understanding Digital SLR Sensor Cleaning
Cleaning Digital Cameras
I have an Evolt and I can confirm that it seems to have done a pretty good job over the 9 months that I have had it.
A couple of months ago I noticed some dirt at low apertures (f12 >). I bought myself a rocket blower and this cleaned all but one spot off, and that one only shows up at about f16. I don’t mind cloning this out in photoshop.
Very generous of Canon to give you a free clean. I’m pretty sure they don’t offer that over here. Olympus definately charge - however hopefully with their inbuilt sensor cleaning technology it shouldn’t need doing that often.
Cheers for the heads up on the cleaning methods. I’ll try those out when it gets to that point.
Jamie: thanks for the feedback on both my piece and the EVOLT. Do let us know how your cleaning routine evolves and if the EVOLT continues to be effective. By the way, what’s the smallest aperture you shoot at?
My understanding of aperture is minimal - I use it mainly to control DOF. I very rarely shoot any anything lower than f11. Except to check for sensor dirt that is.
I have a Canon EOS 1DS which has always seemed to collect dust at every opportunity. A friend with a 10D uses a normal blower with good results - that didn’t do much for my dust problem. I tried the sensor swabs and eclipse fluid: they worked marginally well but not satisfactorily to my taste. I also tried compressed air - no big help. I even took the camera to a local Canon authorized service center. After 2 tries, their results were OK but not an economical (or readily available) option for repeated needs. Then I tried the brushes, swabs, and fluid from Visible Dust. They work the best of anything so far.
Jamie: Given what you said above, your understanding of aperture is more than minimal. However, in my recent experience, shooting at f/4 or wider seems to hide most of the dirt and as you stop down from there the dirt shows more and more. The further you stop down the sharper the focus will be on the “dirt plane.” ;)
Will: Wow, that’s an interesting story. Are you saying that the visible dust brush got more dirt off than sensor swabs with fluid? How is that possible? Thanks for letting us know, by the way.
Another interesting option is a sensor vacuum. I’ve used one on my D70 with good results. I’ve been very leary of touching my sensor with anything. This vacuum deal is a no touch method that seems to work pretty well. Maybe at least to get the larger debris before using the swab.
http://www.green-cleanusa.com
Doug: thanks for the tip, it looks like a great system and given the distance between me and the Canon service center I think I might try it. At the moment my sensor remains clean because I’ve been very good about not changing lenses as much in the field, trying to do it in the car or in the house or in places without wind. When I brought my camera to canon it seemed to have gunk welded to the sensor that would not budge no matter how hard I scrubbed it with a sensor swab. I’d be curious about whether a very strong vaccum would pull that stuff off. What I heard was that canon uses ultra compressed air, that’s dried so it has no moisture in it and blasts the stuff out. I don’t know what they did but they got all but one spec which seems fine to me and I don’t see it at all even at f/22.
Looks like you’ve got a lot of professional experience so your recommendation has quite a bit of weight. Thanks.
hey richard, thanks for the great write up. i’ve been looking into cleaning my rebelxt’s sensor for quite a while, and now that i’ve started shooting weddings i really had to!
anyways, i just finished and i’m about to look at my images full size and i think they’ll be fine. i used the eclipse drops and swabs (which was the only method glazers in seattle even carries b/c they say it is just the best).
great blog by the way. i’ve seen it before from your flickr profile and posts, but i found this particular entry by searching google for “canon service center”. which reminds me.. my brother told me that in LA they don’t really do drop in cleaning anymore (recently). he was living down there this last year and found that out. his friend is fairly promenent photographer and was able to convince them to clean at least one sensor for both of them, but they were insistant that the bodies be left there for longer (days) or mailed (allegidly).
Daniel: I’m delighted you got your sensor cleaned and of course I’m delighted you know me on flickr and now here too.
I’ll call the NJ service center today and ask. I need to have the focus screen on my 5D cleaned and I’d like them to do it while I wait, should I find the time to drive down there. Stay tuned…
I just called the Canon service center in Irvine and was told that he could not give me any information about how much it would or would not cost. I told him I had heard about them cleaning it for free and all I could get out of him was “it may or may not be” and that I’d have to drive all the way there and talk to the person at the counter. Not the glowing service I had heard of :-/
Randy: that’s odd, it really is and I say that because I’ve had nothing but good experiences at the New Jersey Center and I’ve heard that the San Diego center is better and friendlier. I’d try calling back and see if you get someone else on the phone.
I’m sure that sensor cleaning is free at both of these service centers although that’s all that’s free. If you want other parts of your camera worked on or checked they’ll charge you for that. I will say, however, that just last week I went to the NJ service center with both my 20D and my 5D. I was having the 20D cleaned before selling it (it’s sold now) and I not only wanted the 5D cleaned but somehow I’d gotten a few pieces of dirt under the focusing screen and maybe up into the prism. I called them about this and they said that I’d probably have to leave the camera to have that cleaned and it might cost something depending on what was involved. They cleaned the 20D and took another hour with the 5D but cleaned both sensor and prism, no charge and perfectly. I was and am delighted.
I’m sure not every case is like mine, but this is the third time I’ve been to that center and each time I’ve been treated well. I have to say it’s not a pleasant drive through NY and NJ to get there and it’s sort of a dumpy office in a larger Canon corporate park but they do get things done there. I’ve also had two lenses fixed by them, under warranty. I filled out the web forms and sent them in. They kept them for what seemed like a bit too long a time (14 days) but they came back perfect.
I’d try again Randy, my guess is you just got the wrong person.
Thank for the response Richard. I may give them another call, or just show up down there. So is it typical for them to clean it while you wait? That would be great, I was under the impression I’d have to leave it and have it mailed to me.
Randy, all three times I went to have my sensor cleaned they did it while I waited. The minimum time was an hour and max 2 hours. They were busy both times as other people were waiting to have things cleaned. I suppose it would be better if they allowed people to make appointments but they don’t, you just walk in and take a chance. I know, it’s a risk and I drove 3 hours to take that risk but so far, it’s worked out well for me.
You can also mail them your camera body and they’ll mail it back. Or, as you say, you can drop it off and they’ll mail it back. Best to call about this first. Let us know how it goes when you do it.
I have been using the Koh Dustless Bag system recently. It works better than anything else I have used or seen on the market. It has a HEPA air filtering unit that cleans out the air inside the bag and hand ports make it easy to stick your hand in without contaminating the inner environment. I ordered it directly from their website http://www.kohglobal.com. I have been very pleased.
Thanks for this Niles. Is this bag for lens changing, sensor cleaning, both?
Yea, I’ve been using the koh dustless bag system too. You can use the bag for sensor cleaning and changing camera lenses. It’s really cool. Now you don’t have to wait for Nikon or Canon to clean your sensor in their multi-million dollar clean room where they perform the sensor cleaning because you can get a portable clean room for yourself. Check it out: http://www.kohglobal.com
Thanks Sunset, I’ve been doing okay cleaning my sensor on my worktable but it would be nice to be able to change lenses in a cleaner environment than I’m in many times.