Dust spots on your D-SLR’s sensor appear as tiny black specks on the image. There’s a good chance you haven’t noticed the specks—they may only show when you’re shooting a bright subject (such as the sky) at a small aperture. But if those specks have annoyed you, you might remove them from your image using image-editing software like Photoshop. Or you might eliminate them from future shots by cleaning your D-SLR’s sensor.
Several sites on the web illustrate the effects of dust on the sensor (see our Links page). Many also provide cleaning and testing techniques. We’ve tried to learn from these sites as well as from the input we could get from manufacturers. For a good test of your sensor’s health, see our link, How To Make Your Own Tools . From the sheer number of sites, dust on the D-SLR’s sensor may seem like a major problem. It isn’t—film cameras have a much bigger problem with dust on the negative you’re trying to print.
As long as you keep the front end of your D-SLR sealed—either with a lens or with a body cap—you may never have an objectionable dust problem. When you change lenses, try to use a clean area. But, when you’re shooting outside or on the move, that’s not always possible. Then, with the lens removed, dust can enter the camera and migrate to the sensor. Some say the sensor attracts dust because of its electrical charge. Maybe so. But one thing’s for sure—the sensor provides the most objectionable place for the dust to settle.
It’s a good idea to read through the other sites as well—besides providing different techniques, they give you an appreciation of the dangers in cleaning your own sensor. It’s not that the procedure is so difficult—it’s that the cost of a mistake is so high. If you do damage the sensor, expect the repair to cost almost as much as the camera. That’s why you see so many disclaimers, both from the factories and from the web sites. Some manufacturers say you should never attempt to clean your own sensor—always let a factory-authorized repair facility do the job. But that gets expensive. Plus there’s the down time when you don’t have your camera. Other manufacturers go the opposite route—some even provide sensor-swabbing instructions in the operator’s manual.
Your chances for success are greatly improved by using the proper materials and techniques. Plus you should work in as clean an environment as possible—the cleaner the work area, the better your chances for success. To clean the sensor, you must lock up the mirror and hold open the shutter. Now your sensor is more exposed to dirt than ever. If you’re working in an area that isn’t clean, your sensor may end up with more dirt after cleaning than it had before. Good lighting is also important to check the results of each cleaning step.
Please do not attempt to clean your own sensor if you don’t have the proper materials and work area—or if you have any hesitation about your own abilities. Do you have a steady hand? And relatively good eyesight? If not, you might let a professional clean your sensor. That can be expensive. But it’s not even close to the cost of replacing the sensor in your camera.
Since we can’t watch you work—and we know nothing about your qualifications—we can’t guarantee success. Nor can we be responsible in any way for damage—this material is provided at no charge, for your information only. Anytime you expose or touch the sensor, there’s a chance of scratching the filter or causing other damage. And anytime you lock open the shutter, it’s possible to end up with even more dust on the sensor. Some photographers clean the sensor as routinely as they clean the lens. But a few have caused damage that requires replacing the sensor. For some, the danger outweighs the benefit.
If you’re determined to clean your own sensor, we want to offer you the best materials and instructions we can. We believe that the blow-and-swab procedure described here provides the best results outside of a factory facility—at least for most people. Blowing off the sensor sets the stage for swabbing the sensor.
Many of the instructions we’ve seen describe using the SensorSwabs from Photographic Solutions. The products of Photographic Solutions have made the process of swabbing your own sensor a possibility(Without the products of Photographic Solutions, we wouldn’t even attempt this explanation). The SensorSwabs come in three different sizes to match the sensor width.
Pec*Pads, also from Photographic Solutions, are the wipes of choice—soft, absorbent, and lint free, they stand out as one of the safest wipes you can buy. We’ve yet to find anything that matches the Pec*Pads for cleaning optics. At times you may be tempted to cut down a large Pec*Pad™ to fit a smaller Wand. Don’t do it. If you cut the material, your Pec*Pad is no longer lint free.
The SensorWand™ made by Fargo Enterprises, Fig. 1, uses the Pec*Pad at the business end (Fig. 1, shows the SensorWand™ before the Pec*Pad has been wrapped around the rubber tip). But the SensorWand has a cost advantage—you can save money by wrapping the SensorWand with a new Pec*Pad (or, for that matter, you can even make your own SensorWand™—see our link #5, How To Make Your Tools). Also, the square front edge and chisel shape of the tip, Fig. 1, provide firm contact even at the sensor’s corners. The SensorWand™ comes in three tip widths to match the size of your sensor—14mm (shown), 16mm, and 18mm (full frame).
Not everyone uses a Pec*Pad™ to clean the sensor. Some use Kimwipes. Others use quality lens tissue. But we believe the soft, lint-free Pec*Pad™—while not the least expensive wipe—provides the safest and most successful method.
Eclipse™ , yet another product of Photographic Solutions, is by far the preferred cleaning solution. Sensor Clean™ is another suitable solution and is Travel Safe but doesn't dry near as fast and sometimes leaves a film that needs polished off. Traditional solutions for cleaning optics, like isopropanol and denatured alcohol, may dry too slowly. As a result, they can leave a residue on the optic—a residue you have to clean off using a dry tissue. But you should never wipe the sensor filter with anything that’s dry. Although you aren’t as likely to damage the sensor with a moist swab, you will very likely cause damage with a dry swab. Eclipse™ contains methanol. So it dries almost instantly—nearly as fast as you wipe it on. There’s no residue, and you never have to touch the sensor with a dry tissue.
Incidentally, Eclipse™ and Pec*Pads™ have more uses than just cleaning sensors—they’re great for other optics in your camera . If a lens has one fingerprint, you don’t have to clean the entire surface using a spiral motion. The fast drying time of Eclipse™ means you can just wipe off the fingerprint using a moistened Pec*Pad™. You never have to clean off residue using a dry wipe.
What else do you need? You need some type of air blower (we’ll describe the procedures for blowing off the sensor, as well as the recommended air blowers, in a moment). Also, since it’s sometimes difficult to hold the camera steady while you’re cleaning the sensor, you might want a PanaVise (see our link, Where To Buy). The PanaVise holds the camera steady, freeing both of your hands for blowing or swabbing the sensor. You can also tilt the camera to the angle you want. In Fig. 2, we’re using the PanaVise to hold the camera while we’re blowing dust from the sensor.
The first step—locking up the mirror and shutter
The sensor, as you can see in Fig. 2, sits behind the shutter at the film position. A D-SLR allows you to reach the sensor by locking up the mirror and holding open the shutter—normally a “custom function” that’s described in the operator’s manual. If you don‘t have the operator’s manual for your camera, please refer to our link #6, Your Camera’s Cleaning Mode. Yes, you can reach the sensor by holding open the shutter on bulb. But that’s not recommended—there’s too much of a chance the shutter will close when you’re working inside the camera and the sensor is energized making it almost impossible to clean.
With the mirror locked up and the shutter held open, the sensor is exposed to anything floating through the air. Leave the sensor exposed for a minimum amount of time. Don’t leave the sensor exposed while you’re reading the rest of these instructions. Make sure you’re ready to go before you lock up the mirror and hold open the shutter.
Some use a fresh battery when locking up the mirror and shutter. But it’s better to use the AC adapter that comes with the camera (and necessary with some cameras—the sensor-cleaning feature may not work with a battery, depending on the camera). If you’re touching the sensor with a swab and the battery fails, the shutter suddenly closes and the mirror comes down—on top of your tool. You’ve then damaged a shutter curtain (at the least), and the camera has an expensive repair ahead.The second step—blowing off the sensor
Some manufacturers say you should restrict your cleaning to blowing off the sensor with a hand blower. Further, Canon, says you should not extend the nozzle of your air blower below the lens mount. Why? If you have the nozzle inside the camera and the mirror for some reason decides to return, you may have damaged the mirror. Cameras are delicate instruments and require delicate care.
Blowing off the sensor is a recommended first step in cleaning. It’s also a safe step that should not cause damage as long as you’re using a proper air blower and technique. You probably won’t completely remove the dust—the air blower may just get the larger, looser chunks. But those larger bits of dirt are what you want to remove. When you later swab the sensor, a large piece of grit dragged along by the swab could scratch the sensor filter. A scratch on the filter has a worse effect than the dust; the scratch may refract the light, causing a light spectrum to appear in the image. This first step of blowing off the sensor should remove any foreign material that could cause damage.
Here’s a great air-blower suggestion we got from Canon: use a foot-powered air pump, the type of air pump that’s designed for filling air mattresses. Since you’re pumping the air with your foot, both of your hands are free for guiding the nozzle and holding the camera, Fig. 3 (or, if you’re using the PanaVise to hold the camera, you have an extra hand free for whatever you need, Fig. 2).
You can control the power of the air stream—from a healthy blast to a gentle breath, depending on how hard you push on the foot pump. But be warned: the foot-powered air pump is capable of putting out a stronger blast of air than you really want—perhaps even enough to cause damage. Experiment first, noting how you can control the air stream. You’re just removing the loose dirt, not what’s stuck to the sensor. The swabbing step removes the stuck dirt.
When using an air blower, be very careful that you don’t touch the sensor with the nozzle. Touching the sensor with the nozzle will almost certainly cause a scratch—a disaster requiring sensor replacement. That’s another reason Canon doesn’t want you to extend the air-blower nozzle too far into the camera. You may want to try tilting down the front of the camera, hoping the dust will fall out the lens opening.
Some hand-held air blowers include a brush. The idea is that you loosen the dust with the brush. You then use the blower to blow off the dust. But don’t use any brush on the sensor. If you touch the sensor with the brush, you may scratch the filter. And please don’t use canned air. Canned air sometimes squirts a liquid goo—the residue from the propellant—onto the surface you’re trying to clean. See our Where To Buy link for recommended hand blowers.
Using good lighting—perhaps a small flashlight—check the sensor for specks of dust. Magnifiers, such as a watchmaker’s loupe or optivisor, may help. As a matter of fact it will help and save you time. With the optivisor you will be able to see most any dust on the sensor if any is left after a cleaning method. This save time by telling you that you really need to do some more cleaning before wasting your time on another test. The sensor should appear nearly clean after the blowing step; at least those larger chunks of grit you don’t want to scrape across the sensor should be gone. Smaller specks, even though they appear on the image, may be nearly invisible on the sensor. Or they may be stuck to the filter, resisting the air blower. That brings us to the fourth step—actually swabbing the sensor with methanol.
The third step—using one of the many sensor cleaning brushes
If your camera isn't filthy dirty and it isn't your first time cleaning your sensor, this is the time to use your sensor cleaning brush if you own one. A good sensor cleaning brush will keep you from having to go to the fourth step "The Wet Method" quite often and it is much faster.
You don't want to use a sensor cleaning brush the first time you clean your camera as there is a very good chance that you will contaminate it with goo or stray lubricants and it will only make your sensor worse with streaks. It is also a very good idea to clean the walls of your mirror cage/chamber before using a brush. You can always use a brush that was made for a smaller sensor size on a larger sensor but don't use a larger brush on a smaller sensor. Step 1. Use multiple blasts of air from a foot powered blower on the brush fibers for about 5-20 seconds.
Step 2. Do one gentle stroke motion on the sensor from left to right.
Step 3. Use a blast of air to clean the filaments.
Step 4. Repeat as many strokes as possible to cover the entire sensor. MAKE SURE YOU BLAST THE BRUSH FILAMENTS BEFORE AND AFTER EACH STROKE.
The fourth step—swabbing the sensor — AKA "The Wet Method"
Here’s the part of the procedure that’s dangerous—actually touching the sensor with a swab. If the swab is dry—or if there’s any grit on the swab or on the sensor—you could scratch the plastic filter that sits in front of the sensor. It’s then necessary to replace the sensor assembly, a major repair and a major expense. You might want to test your results before proceeding to determine if you really want to swab your sensor. In some cases, blowing off the sensor may be all you want to attempt.
In Fig. 4, we’re lifting the filter from the front of a Nikon D100 CCD (not something anyone would do except for research—taking apart the CCD destroys the unit). Note that the CCD is built into an IC. Perhaps you can now see why it’s so expensive to replace the CCD—the replacement unit includes the CCD package and the control board. For obvious reasons, you never want to disassemble your own camera. Cleaning the sensor, fortunately, requires no disassembly.
The filter sits a slight distance from the sensor. Dust on the filter then casts a tiny shadow onto the CCD or CMOS—that’s why you get black spots on the image. It’s also why the effects show up more at the smaller lens apertures where the shadows are sharper.
At this point, let’s say you’ve locked open the shutter and you’ve used the air pump to blow off the sensor. If you’re using a Panavise, the angle shown in Fig. 2 may be the most helpful. Remove the swab from its protective bag. Although commercial swabs are prepared in clean environments, your work area may not be so immaculate. Use the air pump to blow off the end of the swab before you apply the Eclipse™ or Sensor Clean™. And make sure you don’t touch the end of the swab with your fingers.
Let’s first look at using the SensorSwab as described by Fuji (one of the manufacturers that does provide sensor-swabbing instructions). Fuji says to put a few drops of Eclipse™ on the end of the SensorSwab. Most instructions recommend 2 or 3 drops—the pad at the end of the SensorSwab should just be moist, not oozing solution. If solution seeps under the filter and gets on the sensor, permanent damage may result. Make sure you don’t touch a moist portion of the pad with your fingers—if you do, the alcohol will transfer finger oils to the sensor. Then touch the SensorSwab to one edge of the sensor as shown in Fig. 5.
Tilt the SensorSwab slightly in the direction of movement as you slide it from left to right. When you near the right-hand edge of the sensor, the lens mount prevents you from tilting the SensorSwab. As you complete the sweep, just move the SensorSwab until it’s perpendicular to the sensor. Move the SensorSwab slightly past the right-hand edge to get the dust at the end. If you find you’re leaving dust at the right-hand edge, try tilting the SensorSwab slightly to the left as you complete your stroke.
Since the end of the SensorSwab is moist, dust particles stick to the pad rather than to the sensor. How much pressure should you apply? Several of the sensor-cleaning sites suggest using normal writing pressure. If you use too much pressure, you could scratch or even crack the filter in front of the sensor. Insufficient pressure won’t keep the ends of the swab in contact with the filter or may fail to pick up the dust that’s stuck to the sensor. You might start with light pressure and then increase your pressure as you get the feel of swabbing.
The fast-drying time of the Eclipse™ means you’ll have to work fairly quickly. If you’re not fast enough, the Eclipse™ will evaporate from the SensorSwab—and you don’t want to touch the sensor with a dry swab. You might experiment with the evaporation time. Wet the end of a SensorSwab with a couple of drops of Eclipse. Then note how long the SensorSwab stays moist to determine how much time you have.
Now you can turn the SensorSwab 180° for a second swipe. Repeat the swabbing procedure using the clean edge of the SensorSwab. If you’re using a SensorSwab that matches the width of your sensor, this second swabbing should complete the process. But, if you have to repeat the swabbing, be sure to use a new SensorSwab.
After your first swabbing experience, you can see one problem in cleaning your sensor—the cramped quarters. There’s not much to the swabbing procedure. But the sensor sits in a cramped area that’s difficult to reach. You can’t just swish the wipe across the sensor. Rather you have to change the angle of the swab to reach the entire area. Even though you’re changing the angle, keep the moist end of the swab in full contact with the sensor filter. And keep the swab nearly perpendicular to the sensor for the full sweep.
To illustrate the cleaning technique with the SensorWand, we’ll use the Nikon CCD shown in Fig. 4—it may be a little easier to see what we’re doing. The basic technique has been explained on other sites using different tools. Moisten the wrap at the tip of the SensorWand with 2 or 3 drops of Eclipse™ or Sensor Clean™. Again, avoid touching the moistened area with your fingers. Then place the tip of the SensorWand at one corner of the sensor, Fig. 6; here we’re using the upper left-hand corner as a starting point. Make sure you start at the edge of the sensor—you don’t want to leave dirt at the edge. The chisel-shaped tip of the SensorWand allows you to position the pad fully in the corner.
Hold the SensorWand at a slight angle, tilted in the direction that you’re going to move it across the sensor. Now gently but steadily slide the SensorWand across the sensor in the horizontal direction, Fig. 7. Since the SensorWand supports the full width of the Pec*Pad, you don’t need much pressure. Again, normal writing pressure may be the best guideline.
When you can no longer tilt the SensorWand in the direction of travel, just bring the SensorWand perpendicular to the sensor. Or tilt the SensorWand slightly in the opposite direction. Move the pad a little past the right-hand edge of the sensor (to make sure you pick up the dust at the edge). Work fairly quickly to complete the cleaning before the Eclipse™ evaporates from the Pec*Pad. Now—and only now—lift the SensorWand from the sensor.
Flip the SensorWand 180°. If the width of the SensorWand matches the width of the sensor, the cleaning should be complete. In Fig. 7, the sensor is slightly wider than the tip of the SensorWand. So, for the second pass, we’ll overlap the swipes. One technique is to flip the SensorWand 180° to use the clean side of the pad. Then start the SensorWand at the lower left-hand corner, Fig. 8. Again slide the SensorWand horizontally across the sensor, moving slightly past the right-hand edge.
Alternately, after you make the first swipe, you can move the SensorWand to the lower right-hand corner of the sensor. Tilt the SensorWand to the left and slide it across the sensor from right to left, Fig. 9. Notice that we didn’t flip the SensorWand 180° —by tilting the SensorWand in the direction of travel, we’re using the clean edge. Again move the pad slightly past the sensor edge at the left-hand end while bringing the SensorWand perpendicular to the sensor. We’ve seen a similar technique suggested on a couple of sites.
If you want to swab the sensor again, use a new Pec*Pad. But don’t keep swabbing in pursuit of perfection—danger lurks every time you touch the sensor. Microscopic specks that may show in a test probably won’t be apparent in a normal image. And, even if you do get the sensor perfectly clean, some specks may reappear soon after you’ve used the camera.