Sensor problems

October 18, 2012 • 10:51 am

I appreciate everyone writing in with camera recommendations, which I’ll read carefully before I buy another.  But for those of you who recommend that I stay with my Panasonic Lumix (currently a DMC-ZS8), let me show you how dirt on the sensor ruins the photos.  This happened within one year, and exactly the same thing happened to my previous model—also within a year.  I keep the camera in my backpack in a zippered nylon pouch that is clean.

Despite that, what you see below eventually happens, and someone of my low technical skills is unable to take the camera apart to clean the sensor. The blotches are annoying. And, as I said, the flash overexposes nearly every photo, despite the fact that the exposure is permanently set two stops down, as is my wont.

I don’t particularly want to pay $300 to buy a new camera each time this happens.  And it always happens just when the camera goes out of warranty (not that dirt constitutes a defect!)

59 thoughts on “Sensor problems

  1. At the bottom, I see a cat’s tail being curled, while at the top, I see the outline of a cat’s ear. Ceiling Cat works in mysterious ways and has blessed your photos.

    1. “Apparently dust is a known issue with this particular range of cameras. The dust is sucked in via the lens assembly when the camera is first switched on.”

      Huh. Mine must be old enough that it has a different assembly or something. Or I’ve just gotten lucky so far.

  2. That’s sensor dust, all right.

    You might want to look at cameras rated for underwater usage. They’re going to be a bit bulkier and have a bit less range, but they should be as dust-proof as anything.

    Your only other option is something with a removable lens. Cleaning one is (generally) trivial: remove the lens, do whatever you need to in the menu system to manually clean the sensor, use a squeeze bulb blower to blow out the dust, turn the camera off, and re-attach the lens. 90% of the time, that’ll do the trick.

    For times when that doesn’t work, 90% of the time something like the Arctic Butterfly will do the trick. It’s a close relative of the makeup brush, and all you do is lightly brush the sensor with it a single time.

    And for the remaining 1%? A wet swab works. It’s something you can do easily enough yourself, but it’s not something I recommend unless you’re confident enough in what you’re doing to feel okay self-insuring your gear. It is, however, something that a competent local repair shop should be able to do quickly and cheaply. (Emphasis on “competent” — tales abound of not-competent shops returning cameras dirtier than when they got them.)

    Cheers,

    b&

      1. Off Topic

        With all the camera talk, and you being an obvious photography buff, you came to mind when I came across this image and felt compelled to share it with someone.

        Check this out!

          1. Agreed!

            I don’t have much hope of getting a shot like that, myself…we don’t get aurorae this far south, and I’ve no plans to travel far enough to see them.

            So…I’ve got to get my fix from photos like these….

            b&

    1. That only works for cameras where you can get to the sensor — removable lens cameras, in other words, which Jerry’s isn’t.

      Also, I’d recommend the rocket blower in that link, but not the rest of the stuff. If the blower doesn’t work, use a brush. If the brush isn’t doing the job, either take it to somebody for a wet cleaning or be willing to learn how to do a wet cleaning yourself.

      b&

      1. Ben,

        What I’ve found effective is a small-sized vacuum cleaner nozzle, carefully deployed not to touch anything vital inside the sensor/mirror space (with the mirror locked up). This has worked like magic for me but IT’s NOT FOR THE FAINT OF HEART (or those with shaky hands or bad vision or even bad lighting.)

        I’d love to find another, safer method — that really works! Can you tell me more about the effectiveness of the rocket blower? I’ve read about it but I’ve been skeptical.

        Cheers,

        1. What I’ve found works nicely is a minimalist approach. If you use an air bulb blower in a work area that is dusty, it’s better to use a brush. I use a technique that I employed when I used to do darkroom enlargements and I found dust on the negative. A simple 00 artist’s brush, just slightly moistened and rolled on the tongue to form a point makes an excellent dust nudge. You hardly have to make any contact with the sensor (if at all) to lift the piece(s) of dust off.

          1. I’d caution against both the vacuum and the saliva-moistened brush. I’m sure it’s possible to get acceptable results with either, but there are methods that produce better results with less risk of making things worse.

            The best resource I know for these sorts of things is LensRentals.com. Cleaning gear is basically all they do; they send out a camera / lens / whatever, and the clean it as soon as it comes back.

            Here’s their video on how to clean a sensor. Before watching, let me add a caveat: for most people, for most of their cleaning needs, the very first step with the blower is all you need. For most of the rest of normal cleaning needs, that combined with the second step, the brush, will do the trick. Only proceed to use (or even buy) the stamp if the first two didn’t get your sensor clean enough. And only break out the sensor pen if the stamp didn’t work, and only go to the wet swab if the pen didn’t work.

            http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor

            Any other cleaning questions can be answered here:

            http://www.lensrentals.com/blog/2011/05/the-lensrentals-lens-cleaning-methods

            Finally, I’ll close with the same point that Roger closed with:

            Is All This Necessary? Absolutely not.

            Cheers,

            b&

            1. Thanks very much Ben. Do you find that the specific tool: That rocket blower, is worth buying? I value your opinion on this. (As noted, I’d like to get away from the vacuum.)

              1. Rocket blowers are awesome.

                No dust, no propellants, pressure is limited to safe levels yet still plenty for moving dust around, cheap, durable…yes, do buy one!

                b&

  3. how do you know it is dust? from my skimming, that website above didn’t confirm the pattern as dust.

    not an expert, but could it be radiation damage? cosmic rays regularly impinge upon ccd’s and do not *immediately* lead to hardware problems, but if the same sensors get hit enough times, could this happen?

    also if it is up in a plane enough times, there is a greater chance of radiation hitting it.

    1. I can confirm from experience that that’s dust. It’s a textbook example.

      Radiation damage is exceedingly rare in camera sensors. I’ve never heard of it happening. If it did, it’d affect a single pixel (if a cosmic ray), and it would show up as a stuck or dead pixel. All camera sensors already have lots of those, but they’re mapped out, at least a the factory. Executing a manual cleaning on Canon cameras re-maps them…I imagine other cameras have other ways of dealing with the problem.

      b&

  4. Some cameras (e.g. Olympus) with removable lenses have a vibration function built into the base for removing dust from the sensor. Perhaps you could try externally vibrating your lumix with a vibrator against the bottom of the camera to see if it will remove the dust.

    1. I’d only use that as a desperation measure if you’re willing to accept a very real chance of other damage.

      Built-in sensor cleaning in cameras is done with an ultrasonic motor directly attached to the high-pass filter in front of the sensor and is carefully designed to maximize cleaning whilst minimizing wear.

      Vibrating the whole camera…is more likely to break a contact or jiggle something loose.

      If Jerry wants to attempt to salvage this camera, he’s better off taking it to a local camera repair shop…and probably paying 10% – 20% of the street value of the camera in doing so.

      b&

    1. Oh, and once you have your sensor cleaned, do what I do. I carry my camera in a sealed baggie when I’m toting it around.

  5. How does dust like that get into the camera and onto the sensor? I have had a couple of Canon PowerShot cameras (currently a SX130) and have never seen something like that.

    1. As theshortearedowl quoted above, these cameras aren’t hermetically sealed. As the lenses move in and out, they act like a bellows and air gets sucked in and out. When that happens, any dust that happens to be in the air gets sucked in (and rarely back out again).

      There are designs that can mitigate against this sort of thing. A lot of pro gear has all the moving parts internal, so the lens doesn’t change length (or even rotate) when you zoom or focus. Most SLRs also have an ultrasonic motor attached to the low-pass filter that covers the sensor; dust gets shaken loose to fall in a sticky trap.

      You can tell that Jerry’s camera has a small sensor because the dust is so large in proportion to the frame. On a full-frame DSLR, that same dust would be about the same (proportional) size as those two little feathers sticking out of the vulture’s tail and still be just as fuzzy, making it much less objectionable and much easier to remove in post-production. However, there’s also a lot more surface area for dust to accumulate…the original Canon 5D has a reputation for being something of a dust-magnet. If you didn’t keep it clean (generally with regular wet cleanings), you might have to spend a lot of time in post cleaning up a half-dozen such spots from every frame.

      It’s also worth noting that the problem becomes worse with small apertures and uniform backgrounds. Landscape photographers who include lots of sky and who shoot at f/11 or f/16 are the ones who’re most affected; dust that would ruin such a shot if the dust doesn’t get cloned out in post-production probably wouldn’t even be visible in a candlelit portrait shot at f/1.4.

      b&

  6. Yep – sensor dust sucks. I shoot with a high end DSLR whose sensor is self-cleaning, and I still end up doing the occasional correction in Photoshop.

    Any camera with a zoom lens that moves (and lets in air/dust), or is not airtight, will have dust problems. Here is a list of waterproof/dustproof cameras that may fit your needs:

    http://www.adorama.com/alc/article/11795

  7. So, you work at a University… right? I am sure that there are lab-techs in various departments (perhaps Mechanical Engineering) who have the tools and equipment to quickly clean your camera. Make friends with one (if you haven’t already) and they would probably do the trick in a 1/2 hour for a bottle of wine (someone posted a link to how to clean it.) Buy another version of your camera on ebay or craigslist and keep it as a spare… then when it gets dirty, take it to your friend to clean and pull out the spare. Every camera you get is going to have quirks and functions you don’t like… adapt man!

    1. What’s the point of being a prof if you can’t delegate these problems to your Ph.D’s to manage or sub-delegate ?

      1. I think that it’s JAC’s personal camera, and using university facilities to perform personal tasks is, strictly, not allowed.
        In practice, pints of beer are a wonderfully flexible currency.

  8. Dr. C.: Those blobs would be simply to remove in Lightroom in about 10 seconds, using clone or heal.

    Even better, Lightroom (and I’m sure Photoshop as well) will record where the dust blobs are on your sensor and clone/heal them out on command on each image in the same place — if you decide to use that feature. The magic of good SW!

    Sky or smooth water (or smack in the middle of the main subject’s face or body) are about the only cases where you notice dust, unless you are a pixel-peeper. Of course, that’s exactly where you see it in your shot. Bummer. Sky always seems the worst to me.

    And, of course, inside the camera, the image is inverted and flipped side-side. So, the bottom end of the sensor in the camera (where dust is most likely to collect) is where the sky records if you hold the camera normally. You CAN hold the camera inverted for shots with major sky in them. This also works and I’ve used it in a pinch when I can’t get to my shop to clean my sensor. (The dust blobs end up in the foreground stuff below the horizon and usually aren’t noticeable.)

    This type of thing probably is inherent in these kinds of designs.

    HOWEVER, it’s possible that the Leica version of this camera using additional sealing to prevent this. I’m sure there is a reputable camaera shop in Chi town that can set you straight on that. I don’t know. (I’d hope you’d get something special for all the extra $$ besides a red dot on front!)

    1. “will record where the dust blobs are on your sensor and clone/heal them out on command on each image in the same place — ”

      unfortunately the spots are unlikely to stay in place

      I’d at least inquire from the manufacturer or a local shop if you can find one. Sometimes evolutionary theory should be left to biologists and camera repair to experienced technicians.

      1. They actually are remarkably stable within one shooting session (if you don’t have the US sensor shake thingie.) At least this is true with a DLSR. With this lens telescoping design, maybe not so much.

        In my DSLR’s the blobs have been remarkably stable — especially when I want to remove them!

        1. While it’s true that the dust generally doesn’t move around, it does tend to change character based on aperture, with it becoming more distinct at smaller apertures.

          Some image processing software is intelligent enough to account for that fact; others, not. In most cases, auto / mapped dust removal is “good enough”; in almost all cases, manually dealing with the dust produces better results.

          b&

  9. My Nikon has a “sensor cleaning” mode that seems to work, OK.

    You can also wash your camera by putting it in the pocket of your jeans, using a little fabric softener and setting your washer to the “Delicate” cycle. The jeans help balance out the load during the Spin cycle.

    Don’t tumble dry! I made that mistake once!

    Your camera will be way clean and Downey soft!

  10. Look up Royal Camera Service in Hoffman Estates. Last week, they repaired (replaced a chip) and cleaned my home theater projector in only four days and the price was very reasonable. I’m sure it’d be cheaper To have it cleaned than continually replacing cameras.

  11. My Lumix DMC-TS2 waterproof camera has been a workhorse for over two years, taking great fishing photos all over the world in difficult conditions. I’m ready to upgrade to a new model. There is NO WAY dirt could get into this camera.

    1. Yes, a waterproof camera is one solution; but I don’t think any of them have anything like the zoom range he’s looking for …

      1. In my humble opinion, big zoom is overrated for general tourist-style photography. A wide angle is more useful, for me at least. I can’t remember what zoom Jerry mentioned. 20X? Anything close to that requires a tripod. I use the Lumix waterproof as general, bullet-proof, carry-around camera. It has a zoom of about 10x and a wide angle of 28mm (equivalent). If I need zoom I use a good point-and-shoot. If you’ll forgive the self-promotion just this once, here’s a video I took with that camera at full zoom. I know Jerry likes ducks. A trout rises next to the ducklings at 8 seconds in.

        http://www.youtube.com/watch?v=3zPabTdxzMo&feature=plcp

        That link doesn’t look right in the comment box — hope it works. You may have to fix the line break.

        1. Totally agree on that (my “little” camera has equivalent 24-90mm, f/2.0, and 10Mpixel).

          However: Dr. C. noted that he requires the large zoom range.

  12. If the dust was actually “on” the sensor at least some part of its shadow would be sharp. As the shadows are not sharp anywhere I think the dust is inside the multi-element lens. One way to check is to see if the shadow pattern changes in size as you use zoom. If so cleaning the sensor will not help.

    1. Nope, just like the aperture, if it’s inside the lens elements or even on the front element, you will not see it as a distinct thing, only loss of light and sharpness.

      These are resting on surface of the sensor (by static) there’s nothing to press them into the surface.

      Sensor dust always looks like this until you stop way, way, way down (minimum aperture, probably not acheiveable with this camera setup.) This shot was almost surely shot at the extreme end of the zoom range (long), which makes the DOF super short. There’s virtually no chance it will show up crisp anywhere at this long FL.

      1. Exactly right.

        About the only way to get dust to look somewhat sharp is with an extremely long focal length and a very small aperture…and, even then, it’s going to be on the blurry side.

        b&

  13. I don’t know the details of the Lumix range, but in general photographic work you should have the option of post-processing the image using a “flat frame”.
    Generally, you need to get an image that contains nothing but variations in sensor response including dust on the sensor and optics. This is typically an out-of focus shot of an evenly illuminated field (sky, snow, white wall). The subject image is then XOR’d with the flat fame (in software) to effectively remove the effects of the dust.
    When I was doing a practical astronomy course, we’d repeat the “flatting” procedure whenever we moved between targets ; when we had to close (or open) the dome because of weather, when we swapped team members between targeting, computer management, image processing and image analysis (it WAS a training course) ; naturally this meant that we needed to use the most recent “flat” image for each targete image i nthe processing pipeline.
    Obviously, this isn’t for the “point’n’shoot” brigade. But I get the feeling that JAC isn’t in that brigade already.
    Many software packages have this facility built in, but the name varies.

    1. That kind of processing works well with dark frame substitution of fixed-pattern noise present in long nighttime exposures, but it doesn’t work so well with dust. The characteristics of the blemish from dust change with aperture and focal length…and I can tell you from experience that it’s very difficult to get a suitable exposure of a perfectly-illuminated neutral white object.

      I do that sort of thing as part of the workflow when I’m doing art reproduction, using Robin Myers’s EquaLight software to do the equalization. Even then, I’ll take a fresh blank shot with every scene change (lighting, camera position, aperture, whatever). Generally, I make sure that everything is set up perfectly and then take all the reference shots (including color charts) just the once.

      Cheers,

      b&

  14. I love my LumixDMC, same model as Jerry uses. Can anyone help me with a problem that cropped up in its third year: these damn digital features such as telephoto and image qualities that have appeared on the screen? I cannot make them go away. They change from time to time and make the camera virtually unusable in difficult situations when my finger accidentally hits the lens.
    thanks, Don

    1. Hi Don,

      I have the LUMIX LX5 and maybe the menus are similar.

      Are you wishing to get rid of the text and symbol data on the displayed on the viewing screen while shooting? That should be do-able via the menus. I knwo for sure you can do that for playback mode.

      Can you peovide more info?

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