Keeping Your Image Sensor Clean and Cleaning It When the Time Comes (If You Dare…)

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Keeping Your Image Sensor Clean and Cleaning It When the Time Comes (If You Dare…)

Everyone loves their DSLR. I know I do. But as rugged as these things are, they’re not without their delicate areas. The single most fragile part of your camera is probably its image sensor. So when the day comes that you notice some odd little specs appearing on your photos in the same place and same size repeatedly, there’s a sense of dread that creeps in. Something is wrong, and in all likelihood it’s your image sensor. It’s dirty. Dust has found its way onto it, and if you’re not willing to live with it, it needs to get fixed. The good news is, assuming it’s not a scratch on the sensor and it’s actually just dust, it’s not permanent, so you can fix it.

But first, how did this happen? What did I do wrong? Well, don’t beat yourself up just yet. Dust happens, man. It’s a fact of life. Even if you never change the lens on your DSLR (which would defeat the purpose of having one a bit, wouldn’t it?) dust can find it’s way onto your sensor. The mechanisms inside generate friction and this friction can generate debris, among other things over time. But if you’re like most DSLR shooters you have a couple lenses, you change them, and you don’t do this in a clean room every time… or ever, for that matter. Exposing the innards of your camera to the elements, predictably, has a high likelihood of resulting in some of those elements finding a home in your camera body. These squatters are usually dust particles, and they have little regard for the jurisprudence of property rights you feel you have over that image sensor. So, first, lets explore some ways you can prevent, or at least mitigate the occurrence of dust on that image sensor in the first place:

–       Don’t change your lens! Just kidding… That’s not realistic, but you can certainly be fastidious when picking a place and the circumstances under which you do change that lens. Is there a lot of dust in the air that you can already notice? Is it windy? Moist out? If it is, find a creative solution for the reason you’re thinking about changing that lens and stick with what you’ve got on, unless you can find safer environs for that lens swap to happen.

–       Once you’ve found that safe zone for switching lenses, make sure you’ve turned the camera off. Sensors have an electrical charge that can actually draw dust in like a magnet.

–       Make sure you check the new lens out for dust or any other particles. If there is anything suspicious, clean the lens. It’s safer and easier than cleaning the inside of your camera body.

–       Now that you know your new lens is clean, have it ready to go before you detach the lens that’s already on your camera. So when the swap happens, it’s fast, thus minimizing the window of opportunity for dust to slip inside.

–       While you’re switching lenses, turn your camera body over so the bayonet ring faces down. Just make sure you’re familiar enough with where the index markers on your lens and the body are that you can line them up easily without having to look very much.

Now, lets say you found this article too late and decided to switch from your 28-300mm to a fish eye in a sand storm in Dubai. Brilliant. Now how do you go about cleaning the image sensor yourself?

First, you’re going to need a dash of bravery. This can be an intimidating prospect, so if you don’t feel up to the challenge, don’t do it. Just send it in to the manufacturer to get it cleaned by them, or some other trained technician. Most methods require a steady hand, more than anything. The task is simple enough; you’re just dealing with delicate electronics and the manner in which you will be dealing with them is not covered by any warranty, so proceed with caution and accept full responsibility for anything and everything that transpires with regard to your camera. Any mistakes you make will likely be very expensive mistakes. Consider yourself warned.

First off, the easiest and safest task in doing this is determining whether you might need to clean the sensor in the first place. To do this:

–       Throw a long lens on your camera, say that 300mm number you abandoned that got you into this mess

–       Focus the lens manually to infinity

–       Set your aperture as small as possible, probably f/22, but it can be much smaller depending on the lens

–       Compensate your exposure to +1 or +2 stops

–       Photograph a white, preferably flat, and evenly lit surface from a couple feet away

The idea is to shoot an out-of-focus plane so that the only details you can see are the dust particles that are on your sensor. Then get the image into Photoshop, or something similar, magnify to 100%, and inspect. See a dune’s worth of dust and particles speckling what should be a plain white image? My condolences. Now lets get down to brass tacks.

Clean Up

One note before we proceed: that dust that’s on your image sensor isn’t actually on your image sensor. It’s on the filter that sits before the actual image sensor. Thus the affect the setting of f-stop has with determining whether you have a dust issue or not. That bit of distance between the sensor and the dust gives light room to fall between the two elements in question. The f-stop can focus or broaden the light, changing the shadow dust creates on the sensor. The small f-stop acts as a spotlight of sorts, versus the softer light a wider f-stop would provide.

There are a few methods for cleaning an image sensor, all featuring varying degrees of effectiveness and subsequent dangers. But lets start safe. Well, safer anyway.

The Blower

The safest procedure is to use a hand powered blower also know as a bulb blower. DOT NOT use compressed air. Those have a liquid propellant and can effectively spit on your sensor. If that happens, game over. You can effectively total your sensor requiring a replacement or a whole new camera altogether. When using a bulb blower, don’t place it into the camera body, keep the point no closer than the bayonet. If you accidentally touch the sensor with your blower, you can ruin it as well. Try putting the camera on a tripod and face it towards the ground so that the dust can fall downward, away from the sensor.

Now, the drawback of this method is that you’re not actually “removing” dust. You’re basically moving it around in there, so it settles somewhere else. You also don’t remove particles that have latched onto the sensor.

Brushes

This is getting dangerous now, so proceed with caution, squared. All brushes are not made equal, so when selecting a brush keep certain things in mind. The bristles of a brush used for cleaning a sensor should be very fine and hyperbolically soft, made of a synthetic fiber like nylon, preferably. Though hair is also good because, like nylon, it can hold an electrical charge. Brushes that can do this very important thing are static-chargeable. The advantage of this is that the brush will actually attract and pick up the loose dust particles that are on the image sensor, and not just push them to and fro across it. The handle should be insulated. This just means that it should be a wood, plastic or rubber handle, so as to prevent you from affecting the brush’s static charge.

There are specialty companies that manufacture brushes just for this purpose, but they can be extremely over priced so shop around. You can find a proper brush for under $30 or over $120.

All that being said, there are downsides to using a brush. For one, you have to make sure the brush is extremely clean and free of any moisture or grease from either your fingers or anywhere else. Something- anything- on the brush can potentially damage your sensor beyond repair. If you drag a particularly hard bit of debris across that sensor, you’re likely going to scratch it. This is bad. Then there is the matter of what might actually be in your sensor in the first place. The easiest thing to clear off your sensor is going to be dry, loose dust particles that are just sitting on top, but that’s not the only thing that can end up there. Some debris can be stuck to your sensor, and a brush won’t help you there. Some times a greasy or thicker fluid can find it’s way onto your sensor. Not only will a brush not fix this problem, it can make it exponentially worse by smearing the gunk across the sensor. Then your brush will need a serious cleaning too. When you encounter this, there is only one solution to the problem…

Solvent-based Cleaning (DEFCON 1)

Depending on whom you ask, some might call this the neurosurgery of camera maintenance; others might say it’s the best and only way to clean a sensor. Regardless, the method is simple enough.

–       Get yourself a rigid yet soft slat, like a popsicle stick or the handle end of a plastic eating utensil, just make sure it’s no more than a millimeter or two thick.

–       Fold up a piece of lens tissue repeatedly so that it’s about as wide as your slat, with a bit hanging past the edges.

–       Wrap the tissue around the wide part of your slat. It’ll look a bit like a finger splint.

–       Tape the tissue to the slat so that the end, which the tissue wraps around the slat, is taught but not so much so that it might tear.

Extremely Important Note: do not in any way touch or handle the part of the tissue that is exposed around this end. It will touch your sensor, so contaminating it with finger grease or any kind of debris can be detrimental to the health of your sensor. As a matter of fact, maybe powder-free latex gloves would be a good idea in this endeavor.

–       Now, put a couple drops of a high-quality, non-residue cleaning fluid (like pure methanol) on the end of your hand-made swab.

–       Carefully swab the sensor.

You’re actually touching your sensor, so having the utmost care and an extra steady hand are paramount. So is having common sense. If you lack any of these traits then, again, perhaps just sending it in to the manufacturer is best for you. That being said, we do assume our readership is made up of highly capable individuals.

So there you have it. Try to keep it clean, mitigate the amount of debris and/or dust you get into your camera body, and if you do have to clean your image sensor use extreme caution. Better safe than sorry. Good luck and shoot smart.

 


 

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