Sensor Cleaning

Introduction & Warnings

Originally published in 2005, updated in 2011, and now republished on the brand new Beau Photo Supplies website in 2017, this article is still relevant today, 12 years later! I’ve made a few changes and added some notes to bring this article a little more up to date.
-Mike Mander

This document describes many of the procedures and possible issues with regards to cleaning your own digital SLR’s sensor. It presents this information in painstaking detail and that is certainly intentional! Many are nervous about cleaning their own camera’s sensor and this article attempts to describe the process, and the potential pitfalls, in methodical detail without leaving out any critical points. I even discuss ways to clean that I do not recommend, just so that I’ve (hopefully) covered all the bases. If you are reading this document in preparation to cleaning your camera, and you have any questions at all, please don’t hesitate to email me and ask before going ahead. Before I go any further at all, here is the all important disclaimer:

If you damage your camera while cleaning your sensor, your warranty will probably be void. You will likely be liable for any and all repair expenses – period. Don’t complain that this document led you astray or that a defect or malfunction in the equipment you were using to clean your sensor caused the damage. Any sensor cleaning you perform is entirely at your own risk. Neither Beau Photo Supplies Inc. nor the author of this article may be held responsible should you cause any damage to your digital SLR while attempting to clean its sensor.

If you are unsure of the correct and safe procedures or are too nervous to have a steady hand, you are probably not ready to clean your camera’s sensor! Now that we’ve got that warning out of the way, I will add that I’ve probably cleaned a hundred or more cameras for people over the last several years and so far I have never had a problem – and yes, I too was nervous the first few times I performed sensor cleanings. However, if one uses common sense and is very careful, the risks should be quite minimal. I will strive to point out all the potential pitfalls in this document as I walk you through all the various cleaning methods. However, no cleaning method is absolutely safe and there is always a possibility you could damage your camera!

Also, one more small detail to get out of the way: if you are reading this document and are the manufacturer of a cleaning product for digital SLR’s, please don’t be upset that I have not mentioned your product! I am certainly not familiar with all the products on the market and this is not meant to be a comprehensive overview of every last method for cleaning your sensor!

Update (2017): Beau Photo Supplies is now doing sensor cleanings. You can either make an appointment to just bring your camera in for a cleaning, or you can arrange to watch while we clean your camera’s sensor, and you can ask questions and be given tips.

Part 1 – Don’t Panic!

If you’ve already skimmed through this document, you might be thinking “… good grief! What have I gotten myself into!? I should go back to shooting film!” Please don’t panic – the situation is not all that bad, really! For example, I have been shooting with an Canon EOS-20D for close to a year now and only once have had to resort once to a wet cleaning. Despite the fact that I have made several trips to the dry, windy and dusty desert in the southwestern USA, I have generally been able to clean my sensor with only a few vigorous bursts from a blower bulb.

Update (2017): Sensor resolution is now much higher than the 8MP it was on my old EOS-20D in 2005, and thus smaller particles can be seen more readily and cleaning seems to be needed far more often as a result.

If you spend your days shooting at f/8 and below, you may never even notice that you have a dust problem. The more you stop down the aperture in your camera, the more visible dust becomes. If you stop your lens down to f/22 or more, look out! Every little speck becomes horribly visible. Dust settles onto the glass protective filter that is mounted right in front of the light sensitive part of the sensor. Since this filter is slightly in front of the actual photo-sites (pixels) that capture the image, the dust will generally render as large, out-of-focus, barely visible fuzzy gray blobs. The more you stop your lens down, the greater effective depth-of-focus and the sharper these specks will become on the final captured image.

The other factor which determines how visible the dust will be, is the actual design of the sensor itself. If you have a sensor that has its protective glass cover very close to the light-sensitive portion, you will be bothered by dust much more than if the glass cover sits further away. Therefore some cameras will appear to get dirty far more quickly than others. So far, only one company has bothered to actively address the whole sensor dust issue – Olympus. They have incorporated what they call a “Supersonic Wave Filter” into all their digital SLR cameras. Essentially, the CCD vibrates at ultrasonic frequencies for a few moments when the camera powers on and this effectively shakes the dust off the sensor. In my experience, this system actually works surprisingly well!

Update (2017): These days, most manufacturers are using some form of ultrasonic vibration of the sensor’s low-pass filter and in combination with new low-friction fluorine coatings, many cameras are easier to clean and also stay clean longer.

Part 2 – Quick Start Guide !

If you’re in a hurry to clean your sensor, are new to cleaning and don’t want to wade through this entire lengthy document and are willing to have a go with minimal instruction, here are the bare essentials for you to read to get the job done quickly, simply and relatively cheaply.

Click on the following sections in the order listed, then read the text carefully and make sure you have the appropriate cleaning tools on hand. Here is a recommended starting point – a Rocket Air Blower, a bottle of Eclipse Fluid, several correctly sized Sensor Swabs, a fully charged OEM battery in good condition for your camera, a decent desk lamp or even better yet, a head-lamp and finally, a steady hand!

Update (2017): The reason I recommend an OEM battery is that there are many cheap batteries on the market these days with very poor actual capacity (as opposed to their rated capacity) and many don’t properly communicate their charge level with the camera body. The last thing you want is your shutter closing down due to an unexpectedly weak battery when you’ve inserted a swab into your DSLR and are cleaning the sensor! On a another note, mirrorless cameras (which are getting to be really popular)  pretty much all have their shutter wide open when the camera is powered off, so for those, a fully charged battery is not at all important.

• Read and understand the warning in bold type in the Introduction and Warnings Section!
• Read “Part 4 – Onward to Cleaning”
• Try Cleaning with a Blower Bulb (Part 5 – Light Duty Cleaning – Air)
• If blowing fails to remove all the debris, use Sensor Swabs (Part 7 – Heavy Duty Cleaning -Wet Swabbing)

There you have it. The minimum amount of reading and equipment to get the job done properly and safely. Personally, I use a combination of a blower bulb and, if needed, wet swabs to clean pretty much every camera. However, I strongly recommend referring to this document when attempting other types of cleaning or if you simply want to familiarize yourself with the pros and cons of various different cleaning techniques.

Part 3 – How to check if your sensor needs cleaning?

So, if you want to check how dusty your sensor really is, this is what to do…

1. Put a short telephoto lens on your camera, set manual-focus and focus to infinity. A focal length of between 60mm and 100mm is ideal although if necessary, other lenses can work too.
2. Put the camera in aperture-priority (A) mode and stop the lens down as far as it will go – generally f/16 or higher.
3. Put the camera on auto white-balance and its lowest ISO, usually 100.
4. Fill the frame with a white piece of paper, or point the camera at a blank white wall. Put the camera close so the wall (or the paper) is totally out of focus. Alternatively, point the camera at a featureless cloudy or clear blue sky and perhaps set the focus to its nearest setting to blur out any detail.
5. Take a photo and rapidly move the camera around slightly during the exposure to blur any residual detail that might show at small apertures, although if you are using a telephoto lens, there shouldn’t be anything in focus anyway. You don’t want to use a wide-angle lens for this though.
6. If your camera has a high-res and very sharp rear LCD (2017 update: virtually all do nowadays!), quite often all you need to do is zoom in on the test shot and then pan back and forth, covering the entire image area in overlapping strips, to ensure that you don’t miss any areas during your careful inspection of the image. Many cameras also allow you to switch back and forth between frames while zoomed in, so this is an excellent way of checking how effective your cleaning was.
7. If the camera does not give you a good enough image on the rear LCD, then take the captured image, open in Photoshop (or any other image editor) and zoom in to 100%. Pan around to look at the various parts of the image.

So… after you’ve picked yourself up off the floor, taken some deep breaths and calmed down (OMG, just look at all those dust spots on my sensor!!!), you might want to consider cleaning your camera if there were more than just a few specks visible!

Keep in mind that this “torture test” is often going to show way more dust than will normally be visible in shots that have a lot of image detail or were taken at much wider f-stops. If you only see a few faint faint black specks, I wouldn’t even worry about anything other than a light-duty cleaning by blowing the sensor off (see section below) but if there are tons of specks, smears or little “bubbly” looking spots, you may have to resort to one of the slightly more aggressive cleaning methods outlined below.

You might be thinking, “How in the heck did all this junk get on my sensor? My camera is only a few months old, I have only one lens for it and it never gets removed!” I have heard that question many times and the explanation is that when a camera is new, the shutter and mirror mechanisms will naturally shed some particles due to their initial wear – their break-in period. These fine wear particles can get on your sensor during shooting and cause all the specks that you see. Usually after the camera has seen several thousand frames, this initial shedding will have settled down and become minimal. In addition, some cameras actually arrive from the factory with some dust on the sensor. While manufacturers generally strive to ensure the cameras are as clean as possible during assembly, sometimes a few specks find their way onto the sensor.

How about those “sensor loupes” that give you a lit and magnified view of your sensor? Well, personally, I have yet to see one that is truly effective for very fine specks and at the opposite end of the spectrum, sometimes ones sees “ghost spots” that do not actually show up on images, even when stopped right down. Personally, I only using the rear LCD on modern digital cameras, for many years now in fact, and have had 100% success identifying dust spots and ensuring the camera is clean. I never bother bringing images into a computer to check for sensor dust anymore, except in very unusual circumstances.

Part 4 – Onward to Cleaning

After you’ve checked and found that your camera does have dust on its sensor, the first (and safest!) option is simply to send your camera in to the manufacturer for cleaning. They generally do quite a good job and you have the added assurance that if they screw-up and damage your camera, they would also have to fix it for you at no charge. However, if you have a brand new camera that seems to get its sensor dirty in no time, or if you work in an environment where your camera collects sensor dust fairly often, the factory cleaning option can get expensive and the resulting downtime painful. If you have decided to clean your camera yourself, read on…

Before you start with any of the outlined cleaning procedures, the first thing to do is ensure that your DSLR camera has a continuous and uninterrupted flow of power! You are pretty much guaranteed to cause major damage to the camera if the power should fail and the shutter and mirror mechanism were to try and close down on your cleaning tool! As mentioned before, ensure that you are using a fully charged OEM battery and, very important, use your camera’s sensor cleaning mode – refer to your camera’s manual if you don’t know how to activate its cleaning mode. If you have an AC-Adapter, plug it in as well. In fact, some cameras actually require that you have an AC-adapter plugged in, before they’ll even allow you to switch them to sensor cleaning mode.

Update (2017): I am not aware of any modern cameras that require you to have an AC adapter anymore. Also, I would not bother with an AC adapter as the cable could just get in the way. No issues at all with mirrorless cameras, as mentioned earlier, since they leave the sensor totally exposed when they are powered off.

When cleaning a DSLR, absolutely do not use a bulb (B) exposure mode since the camera’s shutter will close as soon as you let go of the shutter-release! In addition, in bulb-mode the camera will actually be taking a picture, so the sensor may retain a small electric charge which might create a slight electrostatic attraction and make dust more difficult to clean off. At this point, I would have to consider the electrostatic effect quite minimal though – definitely the more important reason not to use bulb-mode is the possibility of accidentally letting go of the shutter-release and having the shutter blades (and mirror) close on your cleaning tool and damage the camera in the process!

Part 5 – Light Duty Cleaning – Blowing the Sensor Clean with Air

Update (2017): I have heard from one particular manufacturer that they actually suggest avoiding blowing off your sensor with any sort of air, due to the possibility of forcing dust underneath the sensor’s low-pass filter, or its cover glass. Personally I am skeptical of this claim since normally low-pass filters have gaskets for ensuring that dust does not get underneath them! I am still using a blower bulb on all the cameras I clean, and while I have seen cameras with debris under their low-pass filter, so far, I can say I’ve never had it happen to me. I personally think that debris under a low-pass filter gets in there during the camera sensor’s assembly process, and it might get missed on an inspection if it happens to be right near an edge and not visible. With time, this debris might dislodge and move to a spot where it can be seen.

So, with that update out of the way, here are some options for cleaning your sensor gently with air, including some not recommended ones for the sake of completeness!

1. Huff and Puff and Blow the Dust Out – Not recommended! With the camera in cleaning mode, take a really deep breath and… well okay, maybe not! Not only is it unlikely that you’ll be able to generate a stream of air powerful enough to dislodge much dust, but you’re very likely going to spit all over the sensor as well and you’ll have a cleaning nightmare from that point on! You may be wondering why I even bothered to mention such an obviously bad method … well, we once had a rental digital camera come back and it looked as though someone had sneezed on its CCD! I’m thinking that maybe someone tried out this “technique”. Just so there’s absolutely no mistake, I do not recommend this cleaning method ! Never attempt to blow your sensor clean with your own breath!
2. Squeeze-Bulb Air Blower – Best Method. Hand-held blower-bulbs, like Rocket Air or Hurricane blowers, are generally very safe since they do not use any liquid propellants and can supply a vigorous (but not overly strong) burst of air. With the camera in cleaning mode, hold it with the lens mount facing down and then use the blower bulb (pointing up) to dislodge any dust with numerous aggressive squeezes of the bulb. Do not insert the end of the blower too deeply inside the camera – I would suggest not going past the camera’s lens mount. This method works for most light dust and dirt but not on any particles that are stuck or “welded” to the sensor’s surface. More on that later. One recommendation is to keep the blower bulb in a clean Ziploc bag, when it’s not being used, to avoid contaminating it in any way. Also, when you buy a new blower bulb, make sure you “exercise” it vigorously for a minute or so – we have had one report of some sort of fine dust that blew out the front of a fresh-out-of-the-box blower bulb.
3. Canned Air (using liquid propellant, like Dust Off) – Use with caution!
   

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   Update (2017): Due to the potential risk of forcing dust underneath a sensor’s low-pass filter, based on the mentioned manufacturer’s warning above, I am now far more hesitant to recommend canned air. Therefore, I have changed the title of this section from “… safe if used with caution” to just “use with caution!” and strongly suggest just using a blower bulb.

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   When used very carefully, canned air is capable of being a fairly safe way of blowing clean a camera’s sensor. However, there are many ways in which one can screw up and potentially cause minor or even major damage! I had been using canned-air for many years and because I was always extremely careful, I never had a problem. I am now using the large Rocket-Air blower bulb for most light-duty cleanings though – I would say this is preferred to using any form of pressurized air. However, canned air does offer more cleaning force and may be slightly more effective. If you insist on using canned-air, here are some very important tips…

   – Never, ever use a full can! Make sure you have used up at least 1/3 of the can for cleaning others things such as lenses or whatever. A completely full can is far more likely to spew out harmful liquid propellant than one that has been partially used. If liquid does spew out and impact the glass cover of your camera’s sensor it potentially could cause the glass to crack due to the thermal shock when hit by the cold liquid.

   – Always make sure that the plastic “straw” from the can of air is firmly pushed into its receptacle and even use some gaffer tape (or other tape) to lock it in place. Bend the straw up at a 45 degree angle as well. If the plastic straw was to shoot out (because it wasn’t held in place securely) and impact the glass on your camera’s sensor, it could easily cause it to crack as well. Bending and taping the straw properly virtually eliminates this risk!

   – Take your 1/3 (or more) empty can of air that has a for-sure locked-into-place straw (bent up at 45 degree angle – can’t be too careful here) and hold it perfectly level and release a few bursts of air away from the camera. Take a close look at the end of the straw when you do this to ensure that you are seeing absolutely no liquid spray out. At this point, do not tilt or move the can anymore until you are finished cleaning! Now take your camera, in its sensor cleaning mode (mirror up and shutter open) and tilt the camera down so the lens-mount is tilted up about 45 degrees from being horizontal and carefully line it up with the straw and move it in front of the canned-air. With the end of the straw still several centimetres away from the lens-mount, start gently squeezing the trigger on the canned-air and direct some bursts into the camera – do not move, shake or tilt the can! To direct the bursts to different parts of the sensor inside the camera, move the camera around, not the can of air. Also, never bring the end of the straw closer than a few centimetres from the lens-mount as canned-air is capable of powerful blasts which might damage the delicate shutter mechanism.

4. “Safe” CO2 Cartridge Blower – Not so good. Although some manufacturers may bill them as being completely safe for cleaning digital camera sensors and they are supposed to be clean, dry and free from any liquid propellant, we have now had several instances of these supposedly “safe” blowers actually spewing out liquid of some sort, most likely lubricating oil. The severity of this liquid spray has varied from a few minor droplets that were easily cleaned using the wet-cleaning technique mentioned later in this article, all the way to huge globs of “gunk” that coated the sensor severely enough that a camera had to be disassembled and cleaned by the manufacturer!
   I will point out that these were isolated incidents, however since we have now heard of problems more than just once, I cannot recommend CO2 cleaning products with a clear-conscience. If you have no other choice, and you have to (or want to) use one of these CO2 blowers, then use the same precautions as for the canned air. You probably won’t be able to safely bend the straw at an angle since they are quite rigid, but since there is not supposed to be any liquid inside the CO2 cartridge, it should be okay to tilt the blower upwards. Just make very sure that you carefully test the blower, especially with a newly installed cartridge, to ensure that no liquid sprays out! Use at your own risk…

Light-duty cleaning – Final Comments

That about wraps it up for the light-duty cleaning methods. The last thing I’ll mention is that it would probably be a really good idea to give the camera’s mirror-box a good blowing-out prior to putting the camera in cleaning-mode and blowing off the sensor. This will help clean out any dust that you might otherwise blow into the sensor area by accident, which might make the cleaning more difficult! Use the same precautions (just to be on the safe side) as when blowing off the sensor, but keep any canned-air spray nozzles even further away from the lens mount to avoid damaging the SLR mirror and shutter. I would try to stay about 10cm away at least.

The last precaution is to try and avoid misdirecting the air too much to one side, angled away from the sensor. I have seen some very small “blobs” of lubricant residue blown off  DSLR mirror hinges or pivots (presumably that was the source) and smear itself onto the sensor with a burst from a canned-air blower. That was quite a pain to clean off! And yes… as cautious as I generally am, it has happened to me…

Part 6 – Medium Duty Cleaning – Using Brushes to Clean the Sensor

This section is dedicated to the use of sensor brushes, namely those from Visible Dust Inc. They have brushes to fit the width of all the common sizes of SLR sensor, from a 1.6x all the way to full frame. In addition, they have other brushes for sensor “touch-up” and travel use, brushes intended for cleaning your mirror-box and even tablets that you dissolve in distilled water to actually clean your brushes if they become soiled. Visible Dust makes a wide variety of cleaning products and I am not going to go into details on the use of them all – for that, please visit the following link, and watch the instructional videos as well: http://www.visibledust.com/videos.php

Make-up Brushes?

There have been a few reports on the Internet, some exceedingly detailed and carefully written, about people buying their own brushes (usually make-up brushes) and preparing them for use in sensor cleaning. The appeal of this is that makeup brushes are, of course, considerably less expensive than the brushes from Visible Dust! However, preparing them involves many cycles of cleaning, rinsing, drying and test wiping on a delicate surface to ensure that they don’t leave any residue or cause any damage. While it’s possible that if you are careful enough and take extraordinary care, this method may also be safe… however I cannot endorse it here since there are absolutely no guarantees on brush quality or cleanliness, or on an individual’s ability to prepare these brushes properly. There are some people who seem to be having success but if you want to try this, good luck – you are on your own.

Although expensive, keep in mind that the brushes from Visible Dust are meticulously prepared and inspected to ensure they are of the absolute highest quality and are utterly clean and safe to use on your camera’s sensor. I would suggest that due to their longevity and effectiveness, their one-time cost, although somewhat steep, is a small price to pay to ensure that your expensive digital camera can be cleaned as safely and efficiently as possible!

Speck Grabber?

There is also a product type I thought I’d mention, one of which is called the “Speck Grabber”, and it has a special type of rubber tip for picking up dust. You are supposed to reach in with this and touch any specks of debris on your sensor and lift them out. Nice in theory perhaps, but in practice it is virtually impossible to see the vast majority of specks that may be contaminating your sensor. While I have had limited success using this tool to remove very obvious large specks, bits of hair etc., I generally don’t find it all that useful. Sure, you can use any of a number of different “Sensor Loupes”, magnifiers that have their own light sources and are supposed to help you find the dust, but I still find it very difficult to see the smallest particles with those loupes, so using a speck grabber is not very effective. In addition, you need to keep the rubber tip extremely clean since otherwise it may leave a mark or smear on the glass of your sensor, which will then require a wet cleaning to remove!

Onward to Brushing

Update (2017): Visible Dust no longer sells just the brushes, the kind that you spray with compressed air to give them an electrostatic charge. Visible Dust still has a product called the “Arctic Butterfly” which uses a motor to rapidly spin the brush, it order to give it a static charge, so you won’t need to use compressed air. However, I am leaving in all of the following info regardless, just in case you still have one of those older brushes, or have bought new old stock from a store recently…

I would suggest that the initial step is to clean your camera’s mirror box as best you can. You can either use one of the light-duty air-based cleaning methods that I mentioned earlier (see “Final Comments” in Part 5 – Light-duty cleaning) or you can use a Visible Dust brush dedicated to this task. By “dedicated” I mean that you should never use the same brush for cleaning the mirror box and for cleaning the sensor. When brushing the mirror box, you could inadvertently pick up some lubricant or other residue and then transfer it to your sensor if you use the same brush! At that point, your only option would be a wet cleaning. Again, since Visible Dust provides such detailed instructions, I won’t bother repeating everything here, so see the video link near the top of this section for more info. A third option is to use the Chamber Clean kit from Visible Dust. This is actually a wet-cleaning of your mirror box using a special liquid and swabs, and it will remove even more particulate matter and residue than blowing or brushing would.

Once your mirror box has been cleaned, you need to prepare your camera for sensor cleaning as described in the Part 4 – Onward to Cleaning section above. Namely, ensuring you have a fully charged battery or even an AC power adapter and putting the camera into its sensor cleaning mode. The basic procedure for the use of the sensor brushes is to “charge” them with compressed (canned) air before use. Blowing them for several seconds with canned air will remove any dust particles, ensure that the brush fibers are totally dry and give them a slight electrostatic charge that will attract the dust on your sensor and allow it to be swept up, clinging to the brush, and not just pushed around on the sensor.

Once your brush is charged, your camera is in cleaning mode with the shutter open, and the sensor exposed and you’ve got enough good light to see by, carefully insert the brush through the lens mount and down to the sensor. It may be a good idea to insert the brush while rotated at a 45 degree angle until it is almost touching the sensor and then rotate it again to line it up for the cleaning stroke. Start with the brush at one end of the sensor and lightly stroke it across to the other side with just enough pressure to slightly flex the brush fibers. Lift the brush off slightly, rotate it to a 45 degree angle again and lift it out. Rotating the brush at an angle while inserting and removing it gives you a little more clearance and makes it less likely to touch the mirror box walls and possibly contaminate the brush. At this point, clean and charge the brush with compressed air again and do one more swipe, just like before. When you charge the brush again, make sure your air stream is not blowing towards the open camera! That’s all there is to it! At this point, unless you have “welded on” spots of dirt, clinging pollen grains or oily smears, your sensor should be totally clean.

Visible Dust also makes a lighter duty touch-up brush that is thinner and has fewer brush fibers. This allows it to be cleaned and charged effectively with only a blower-bulb rather than canned air. This is ideal if, for example, you are traveling by airline and are not permitted to carry canned air on board the flight. The procedure for its use is essentially the same as the normal thick brushes but it may not be as effective and require more than the usual 2 passes to get all the dirt off. Also, if you have dirt that is slightly stuck to the sensor, the normal heavier brush might be more likely to dislodge and lift these particles off than this lighter duty brush.

It may take a bit of practice to get good at this but not to worry… there is very little risk to your sensor by brushing. Visible Dust has done a long-term cleaning test with a Canon EOS-20D digital SLR. Even after 10,000 strokes, the equivalent of over 8 years of daily cleanings, there is no visible damage – no streaks, no scratches and no marks on the camera’s CMOS sensor. Sounds pretty darn safe, if you ask me.

One important point is that after you brush your sensor and re-check the camera (as described above in “How to check if your sensor needs cleaning?”) look carefully for any new smear marks. If you see a fresh smear, it could indicate that somehow you’ve contaminated your brush prior to your last cleaning. At this point, you will need to resort to wet cleaning and (very important) do not use your sensor brush again until you have cleaned it thoroughly! You will otherwise just risk smearing your sensor again. Again, see Visible Dust’s website for their instructions on how to clean your sensor brushes, should they become soiled. Visible Dust recommends you clean your Sensor Brush after every 20 or so sensor cleanings.

A few additional notes… make sure that you are very careful not to touch the brush fibers with your fingers and always put the brush back into its plastic case. Do not touch anything with your brush other than your sensor! Also, try to avoid dusty environments when you’re cleaning and make sure you don’t speak while poised over your open camera – in other words, don’t go fumbling for your cell-phone if it rings while your camera is open for cleaning! And that goes for all the other cleaning methods as well…

That’s about it for brushing – simple, safe and it can be effective. In the next section, I’ll cover methods of cleaning that will strike fear into the hearts of… well hold-on, wet cleaning is not all that scary – honest!

Part 7 – Heavy Duty Cleaning – Wet Swabbing

Okay… now the gloves are off – no more Mr. Nice-Guy! You’ve got crud or smears on your sensor and no amount of blowing or brushing is getting them off. Time to call in the big guns! We’re talkin’ wet cleaning here, and it’s the most aggressive way I’ll be describing to clean your sensor. If this doesn’t work, you’ll have to send the camera in to the manufacturer since I am not going to describe any cleaning methods that are more vigorous!

Note that wet cleaning is potentially the most dangerous of the methods discussed here since you will wiping a cleaning pad across the surface of the sensor while exerting a decent amount of pressure. What could be dangerous is if you somehow manage to get a minute grain of sand or other very hard particle trapped under the pad and then drag it across the sensor, possibly scratching its cover glass in the process. The best way to minimize this danger is to always clean the inside of your camera as thoroughly as possible, first with one of the light duty (air) cleaning methods described earlier and then perhaps even following up with a thorough medium duty (sensor brush) cleaning. At this point, there should no longer be any larger dirt particles anywhere to be found inside the camera, so the wet swabbing should be quite safe at this point. I will be discussing two basic type of swabs, the Sensor Swabs from Photographic Solutions Inc. and the swabs from Visible Dust, both used together with the Eclipse cleaning fluid from Photographic Solutions.

On Cleaning Fluids

My go-to cleaning solution is definitely Eclipse Fluid by Photographic Solutions. I find that 95% of the time, or more, I can get a sensor clean using just Eclipse. Once in a while, there might be very stubborn smears or streaks, and for those I may need to use Visible Dust’s Smear Away solution. However, I often find that smear away actually leaves some streaks on the sensor and thus will follow up with another swab moistened with Eclipse. I have also come across some small specks, or even salt residue from beach spray, that is impervious to alcohol based fluids, like Eclipse, and in those cases, carefully using distilled water with a swab, and then following up with Eclipse on a final pass, has done the trick.

Photographic Solutions – Sensor Swabs

Sensor Swabs have been around since the early days of digital SLR’s and are the “original” self-serve cleaning solution for digital SLR’s. The swabs come is 3 sizes for a perfect fit to your camera and are specially designed, single-use, lint-free cleaning pads mounted to a flexible plastic blade. The swabs are manufactured and individually packaged in a clean-room environment and are absolutely guaranteed by Photographic Solutions not to damage your sensor when you follow the proper directions. The flexible plastic stem of the swab is designed to bend when the perfect amount of safe cleaning pressure is applied so you don’t need to be afraid of pressing too hard and cracking the glass on your sensor! Eclipse cleaning fluid is an ultra-pure alcohol-based fluid that leaves absolutely no residue when it evaporates and has always been my fluid of choice when it comes to wet swabbing. Together, the swabs and fluid are a very effective cleaning method when your sensor has stubborn, stuck-on dirt, streaks or smears. I had used them for many years now and they have proven very effective.

Visible Dust – Orange and Green Swabs

Visible Dust has a range of products and I like their swabs quite a bit, slightly better in fact than the original sensor swabs. Their handles are a little firmer and flex less, making it easier to clean across the width of your sensor and maintain a consistent pressure. They also have a perforated plastic support inside the swab part than can hold more fluid, should you actually put too much on by accident. Since the handles are a bit stiffer, you will need to exercise a bit more caution though so as not to press down too firmly. Visible Dust makes “Orange” and “Green” swabs, which use different cleaning materials, and different coloured handles, orange or green of course, so you can distinguish them. The green swabs seem to use more of a symmetrical-weave artificial fibre fabric (like cloth) and the orange swabs use more of a soft random-weave fibre material, similar to lens cleaning tissue, or to the original Sensor Swabs from Photographic Solutions.

Personally I prefer using the orange swabs (with Eclipse fluid) since I find they get rid of stuck-on particles better than the green swabs. In addition to the differing widths of swabs (1.0x, 1.3x, and 1.5/1.6x) Visible Dust also make very narrow “corner swabs” and more recently, they’ve also got really wide swabs for use with medium format digital backs.

Corner swabs are useful if you find that regular swabs are pulling “gunk” in along the edges of the sensor, which can happen sometimes with brand-new cameras. Some manufacturers seem to clean sensors at the factory by “pushing” gunk off to the edges (purely speculation on my part based on what I have seen) which can then get dragged back in again when a full-width swab is used. With the corner swabs, you can firmly drag one along all four edges of the sensor and then follow up with a regular width swab.

Home-Made Sensor Swabs?

Again, there are many instructions floating around the Internet on how to construct your own cleaning swabs, with the most famous probably being the “Copperhill Method.”

Update (2017): I actually have no idea what is out there these days as far as home-made solutions and whether or not the Copperhill Method is still being touted? I really think it best to use proper swabs that are designed for the task! I have now cleaned thousands of cameras over the years and have never once scratched a sensor or damaged a camera. I’d suggest spending a few dollars and buying the right tools for the job! In any case, I am leaving the following section in regardless…

The author of the Copperhill Method has taken great pains to describe the (hopefully) safe use and construction of cleaning swabs and many people are using the method successfully. So, while the Internet does indeed have some very detailed instructions with many good tips on how to safely construct and use these swabs, they invariably rely on using “Pec Pads” wrapped around some form of home-made or purchased “spatula” that is the correct width for your camera’s sensor. Pec Pads are also manufactured by Photo Solutions, the same company that makes the Sensor Swabs, however they are not made of the same material and have not been tested or approved by any camera manufacturer. Photo Solutions does not recommend or warranty Pec Pads for use in cleaning digital camera sensors! Pec Pads are intended for cleaning lenses and other optics, not sensors! Please read: Photo Solutions’ warning against using Pec Pads for sensors!

Even accepting that Photographic Solutions is, perhaps, being a little overly cautious with their warning, another problem is the handling required to cut and wrap a Pec Pad around your home-made cleaning spatula. You would need to be extraordinarily careful not to contaminate the Pad with dirt or oils from your fingers during its assembly. Remember, Sensor Swabs are hand-constructed in a clean-room and individually sealed in plastic bags. You cut the bag open, remove the swab by its plastic handle and immediately use it for cleaning, so there is virtually no chance of contamination. As you can imagine, there are many more ways you could go wrong with the home-made swabs. Your CCD or CMOS sensor is the single most expensive and critical part of your digital camera, so you will have to decide how much your piece-of-mind is worth…

Before using the wet cleaning method described below, remember to check the  Part 4 – Onward to Cleaning section on how to prepare your camera and also clean your mirror box as outlined in “Final Comments” in Part 5 – Light-duty cleaning.

Instructions – Using Sensor Swabs

Each single Sensor Swab or Visible Dust Swab comes individually wrapped in a small plastic bag. Please note that the following instructions are only for the use of Sensor Swabs made by Photo Solutions Inc. or the  – they are not necessarily safe instructions on how to use any other third-party or home-made swabs! Here is the step by step…

1. Ensure you have good light to see by, prepare your camera and place it in cleaning mode as described earlier.
2. Open your bottle of Eclipse fluid, or, your sensor cleaning fluid of choice. I would suggest that, at minimum, ensure you have at least 2 new Sensor Swabs on hand.
3. For Sensor Swabs, cut the swab’s plastic bag open on the end opposite the “business end”, or swab portion of the tool, and carefully pull the swab out by its handle, being careful not to touch the business end of the swab with anything. With the Visible Dust swabs, the bags have a glue fastened lid which you can peel back without needing to cut the bag open, however make sure you fold the opened flap securely back, holding it in place with a finger, to ensure that the swab does not touch this little flap when you pull it out. You wouldn’t want to transfer any glue to the business end of the swab of course!
4. Carefully place only a few drops of cleaning fluid right on the end of the swab, evenly distributed across the width of the swab’s cleaning pad. If you are using a cropped sensor (1.5x or 1.6x) swab, use 3 or 4 drops, for a swab meant for a full-frame sensor (1.0x), use about 4 or 5 drops, and use 6 or 7 drops for the digital back swabs. With the small corner swabs, one small drop is all you will need. Whatever you do, make sure you do not saturate the pad – you wouldn’t want to risk any fluid actually dripping off the swab! Again, the perforations in the Visible Dust swabs makes them less likely to drip if you accidentally apply too much.
5. Insert the swab into the camera, being very careful not to touch the swab with anything, and place it in contact across the narrow width of the sensor right at one end. Gently push down on the swab at a small angle until the handle of the swab flexes slightly, and stroke the swab with even pressure and at a slow, even speed, across the width of the sensor. The correct speed means you’ll take maybe 3 to 4 seconds to move across the sensor’s width. Don’t be afraid of pressing down; the swab’s handle should definitely flex a little! Too light on the pressure and it won’t clean effectively. Try to keep the swab centered perfectly when stroking across the sensor and avoid letting the swab “snap” straight (lose its flex) when you near the other side of the sensor. This can take some practice! Important: as I mentioned above, these directions are not for use with home-made swabs. Some of these are constructed of fairly rigid plastic and will not flex at all! In addition, the digital back swabs generally have completely rigid handles, so you will have to judge the pressure for yourself – definitely don’t try to flex those!
6. Lift the swab out, spin it around 180 degrees to use the other side of the pad’s edge, reinsert into the camera and repeat step 5 in the same direction across the sensor. Swab manufacturers will often suggest changing direction, in other words, first swab one way and then swab the other way, however I find that this will sometimes just push particles back and forth across the sensor, ones that might otherwise just get pushed off the edge and out of the way. It is definitely easier to clean by always maintaining the same direction of swabbing in my view. If have not had any issues with any “build-up” on one side of the sensor with this technique, however make sure you continue to always swab in the same direction.
7. After the second stroke, lift the swab out and discard it immediately! Never use any side of the swab more than once as it may have picked up contaminants from its first use. Not only might you put dirt back on the sensor, you also run the risk of scratching your sensor if, in the unlikely event, the swab has picked up a piece of grit. Also never put the swab down and then pick it up and re-use it later. The swab should go right from its plastic bag to cleaning the sensor without ever being put down or touching anything else! Do not take any chances with your camera! If you have used the alcohol-based Eclipse fluid, proceed to step 9.
8. If you used a non-alcohol based sensor cleaning solution, and the sensor still looks quite “wet” to you, to speed things up you may take a dry Sensor Swab (fresh out of its bag!) and lightly wipe across the sensor as in step 6 but apply far less pressure so the swab does not flex. Discard this swab also. Better yet, simply wait a little longer in step 11 as the fluid should eventually dry without leaving any residue – this will also save you the cost of another swab! I like to leave the camera in cleaning mode (shutter open) for a few moments (5-10 seconds or so), after cleaning, to allow any residual fluid on the sensor to evaporate and clear out of the immediate vicinity of the sensor. Make sure the camera’s lens mount is facing downward at this point to prevent any new airborne dust from settling on the sensor.
9. Take your camera off of its cleaning mode.

That is basically all there is to it. Please be careful in step 4 not to put too much cleaning fluid on the pad. You definitely do not want the pad sopping wet! Also note that Eclipse fluid evaporates quite quickly, so do not delay after moistening the pad – use it for cleaning quickly before the pad has a chance to dry.

At this point you will want to check how clean your sensor is, as described in Part 3 – How to Check if your Sensor Needs Cleaning, and if it not yet clean enough for your liking, repeat steps 1 through 9. If the camera’s sensor is very dirty, you may need to use several swabs to get it totally clean. My absolute worst case cleaning for someone required the use of a dozen swabs – the sensor was unbelievably dirty! However the camera was essentially spotless afterwards.

Final Thoughts on Wet Cleaning

If, after cleaning, you see little trails of particles that seem to have dragged in from the edges of the sensor, you will want to do a pass with a corner swab. I use one swab with one small drop of fluid and clean two edges of the sensor with one side of the swab, and the the other two edges with the second side. Then go back and repeat the cleaning with a normal swab as described above. Note that I usually find that corner swabs need to be used only during the first few cleanings when a camera is new. Once any residual edge gunk has been cleaned, the regular swabs are generally all you will need.

After you’re done with swabbing and have checked your sensor again, occasionally you might see some new spots, larger particles or some random specks, and those might be tiny bits shed by the swab material. Usually just cleaning the sensor with a blower will get rid of those, however you may need to resort to one final swab at times too.

On average, I use about two swabs for most cleanings. If I find that the correct size of sensor swab is just barely wide enough for the camera’s sensor I’m cleaning, I will first “hug” one side of the sensor, and then the other, with the two passes of the first swab. Then, with a second swab, I will do the two strokes centered down the middle. Just don’t hug the sides so close that the side of your swab tip touches and drags along anything in the camera, potentially scuffing bits of material off the swab’s pad and contaminating the sensor with new bits of junk!

Update (2017): I see that Photographic Solutions now has a thicker “Sensor Swab Ultra” now which requires more fluid than what I originally described above. I have not used these swabs personally, so have no comment on their effectiveness.

There are many new cleaning supplies out there, from anti-static mats, to fancy sensor loupes with multi-coloured LEDs, to ionically charged blowers and more! Just because I haven’t discussed a certain product here doesn’t mean that it isn’t good, or effective at helping you clean your sensor. There is simply too much out there for me to test! However my old standby method of Rocket Blower, Orange Swabs and Eclipse fluid, with an occasional other fluid thrown into the mix when a particularly difficult sensor comes my way, has so far worked on everything I’ve had to clean, and I’ve never damaged a camera as yet. Knock on wood!!!

Some Final Random Comments on Cleaning

If you live in a predominantly dusty and dry climate, you might find that the light or medium duty cleaning methods (non-wet) are all that you’ll need the vast majority of the time. If you live in more humid climates or change lenses when a lot of pollen spores are in the air you might find more sticky dirt will accumulate and require the occasional wet-cleaning. Industrial environments can be bad as well if there are oil-based vapors or fine oil-mists suspended in the air. Avoid changing your lenses is such environments whenever possible!

Use simple common sense when changing lenses too. If it is windy, try to use your body as a shield to prevent dust and dirt from entering the lens mount. Never leave your camera open with no lens mounted and no body-cap. If you share lenses between film and digital bodies, make sure the mounts on the lenses themselves are clean so as not to transfer dust to the digital camera.

And some photojournalists – yikes! There seems to be some sort of macho “Hah! My gear is more thrashed and filthy than yours!” mentality going around amongst some of them. The frequent lens changes some of their cameras must suffer through too… damn but I’ve seen the chrome worn almost completely off of a camera’s lens mount. When you look inside the really bad cameras, there are fine brass particles abraded from the lens mount glittering in the mirror box like gold dust! Dirty sensors? Oh you betcha, and how! I’ve seen so many brass shavings in a photojournalists’s digital SLR that I was surprised it was still working and didn’t short out in a puff of smoke! Come on guys, treat your expensive gear with a little respect!

Update (2017): After reading my old “photojournalist rant” above again (which actually made me laugh), I have to say that these days, it seems they are treating their gear more carefully! The few times I’ve done cleanings for PJs in recent years, well the cameras were no worse than those from a regular pro or amateur. The old “film camera days mentality” of being super hard on their gear seems to have worn off, ha!

You might want to know how I clean the sensor on my own digital SLR? Well I previously used canned-air very successfully but now just use a large Rocket-Air blower for light duty cleaning. While not as powerful, I have found the largest Rocket blower sufficient for any loose dust and dirt particles. If there are “welded” specks, my preferred wet-cleaning has been to use Eclipse Fluid and Orange Sensor Swabs.

Lastly, as far as camera manufacturers are concerned, the only “officially” endorsed method (as of this writing) seems to be the use of Eclipse Fluid and Sensor Swabs from Photographic Solutions Inc. and only by two manufacturers – namely Fuji for their S1, S2 and S3 cameras and Leica for their new Digital-Modul-R. As far as I know, none of the other digital-SLR camera makers endorse any cleaning methods where the end-user is required to actually touch the sensor with any sort of swab or brush.

Update (2017): I am currently not aware of what any manufacturer’s official stance is on cleaning one’s own sensor. I think I will contact Canon, Fujifilm, Hasselblad, Nikon and Sony to hear their thoughts on this, and when I do, I will update this article…

Well, that about wraps up this massive missive! Congratulations to anyone who actually managed to read the whole thing!!! Hopefully by now you are comfortable with the procedures for cleaning your own digital SLR sensor. I certainly hope I have covered all the points of concern in enough detail, and answered all your questions. Please, if you find any errors or feel there are any omissions in the information I have provided, do let me know and I will endeavor to correct or expand this article. I appreciate any and all feedback…

Previous Update (Jan. 15, 2011): Updated the article to mention the new Visible Dust orange, green and corner swabs. Removed the Visible Dust Cleaning kit info, the one with the big “Q-Tips” since it is no longer available and was never that great a way of cleaning your sensor. Updated the recommendation on swabbing direction (always go the same way!) and described cleaning with corner swabs. Added some detail on opening the individual Visible Dust swab bag, with respect to the glue strip they use. Added note about “sensor loupes” and checking for dust on a camera’s rear LCD. Fixed and/or removed various dead URLs, pointing to manufacturer’s websites.