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Background

I have a Panasonic Lumix compact camera, which, out of nowhere caught some piece of dirt between the lenses or on the sensor. I ensured that it was not on the outside of the lens. When zooming (optically), it didn’t change size or position, but at best became more or less diffuse (but never sharp). Here is what the lower left quarter of a photo looked like:

lower-left quarter of a photo

I tried exposing the camera to moderate forces (shaking, spinning) at different lens positions (i.e., optical zoom levels), but the particle didn’t move at all. I didn’t open the camera. Then when I tried to take another picture to demonstrate the effect to you, the thing was gone as suddenly as it came. Obviously I something I did caused it to move, but I have no idea what.

Actual question

My problem got solved by luck, but I am wondering what targeted efforts I could have made. Hence I ask: If a piece of dirt gets stuck somewhere in the optical path of a compact camera, what are possible actions that may remove it? I am only interested in solutions that do not involve disassembling the device.

  • Well think about it, if you have a piece of dirt inside the lens how can you remove it if you can't shake it off? You can't. But you could do it in post processing like Lightroom etc. – Emil Aug 6 '17 at 10:36
  • Well think about it, […] how can you remove it if you can't shake it off? – I thought and I had no idea. But then it’s very hard to assure the non-existence of something, in particular on a subject on which you are no expert like me with cameras – at the end of the day a trick that is obvious isn’t a trick. If you have a compelling argument that there is nothing to be done except arbitrary shaking, I would consider this a valid answer to the question. However, please consider the different involved phenomena (mechanics, electrostatics, …) and the complexity of the device. – Wrzlprmft Aug 6 '17 at 10:52
  • I didn't mean it as offense, and I didn't think what I was saying qualifies as a complete answer, hence I put it in the comment section. My comment isn't meant to put you down, so I didn't vote down your question as I don't think it's impossible. It's more of a brain-storming, you know? I'm no stranger to mechanics, so I do have some expertise with these things. – Emil Aug 6 '17 at 11:30
  • @Emil: Don’t worry; I was neither offended nor put down. – Wrzlprmft Aug 6 '17 at 11:52
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If you ever do have something stuck inside a device that doesn't decide to leave on its own, your options for removal are pretty much the following:

  • Shake the device and risk causing impact damage if you accidentally strike it against something or drop it. I've never had shaking remove particles that were already stuck in place, yet it's still the first thing I try.

  • Use a vacuum cleaner to create negative pressure which might (re)move the object. This also risks damage to the device if the suction is too powerful and the device poorly built. I have done this to successfully reduce dust in zoom lenses, but there's no guarantee that particular specks will be cooperative.

  • You can also try slipping strips of paper through gaps between components. This risks making things much worse when the paper tears.

  • Disassemble the device. This is what you want to avoid, but it's the only reliable way to get inside the device to clean it. Disassembly also risks damage beyond repair.

    • Have someone else disassemble and clean the device, preferably someone at a service center. Costs more, but less risk of damaging the device.

    • Now is the time to do an IR conversion if you were considering it.

  • Remove the speck during post processing, as Emil suggests. Create a layer mask and use content-aware infill. Reuse the layer mask for all affected images. Most annoying solution, but least risk of damage to the device.


Normally I don't worry about dust that isn't visible unless the lens is stopped down past F11, but then I noticed a huge speck in my compact camera with the aperture wide open. Took some test pictures to see if I could live with it. No way.

Checked the front element, nothing there. Shook the camera, even though I "knew" it wouldn't help, and as expected, no improvement. Tried to suck the dust out with a vacuum cleaner. Some improvement, possibly imaginary, but that huge speck didn't budge. Briefly thought about slipping paper through the gaps in the lens barrel. Then thought better of it.

Decided to disassemble the camera. Removed the outer casing. Removed a few ribbons. Removed and loosened some screws until the lens was just loose enough to use a blower and slip a dry swab through to the sensor. Made a few quick swipes. Partially reassembled to test. Major specks gone. Finished reassembly. Swore never to do again. (But probably will if I have to.)

  • 1
    Hint about disassembling any optical device, BTW: If you can easily snap or twist off a plastic cover at find two dimples or notches on a retaining ring, that retaining ring is designed to be taken off for maintenance. Calipers, tweezers, wood strips with two nails in it, or very wide and thin pliers can sometimes open these - however, probably most people that dabble in optics tinkering will have the $25 tool that is intended for that use.... – rackandboneman Mar 5 at 9:12
  • @rackandboneman – Are you describing a lens spanner? – xiota Mar 5 at 9:23
  • Yep, word escaped me since I didn't tighten the thumbscrew on it enough :) – rackandboneman Mar 5 at 13:03
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If it doesn't change size or position when zooming then it isn't in the lens - it is on the front of the filter stack of your camera's sensor. Most digital cameras have a stack of filters directly in front of the sensor that limit infrared and ultraviolet light from reaching the sensor and affecting the image. They also usually have a low pass/anti-aliasing filter in the stack as well.

When dust or other small debris gets on the surface of the sensor stack the shadow of the dust is cast upon the surface of the actual sensor a couple of millimeters or so behind the front of the stack. At longer focal lengths and smaller apertures the light striking the sensor is more collimated and the outline of the dust/debris will be sharper and more distinct. At shorter focal lengths and wider apertures more of the light striking the sensor will be at an angle that will make the shadow fuzzier and less distinct.

In your case, the shaking you subjected the camera to was enough to dislodge the foreign particle from the front of your camera's sensor stack.

After the shaking, the particle was still there as ever. Only several minutes, photos, and other actions later, it was suddenly gone.

Well, the aggregate of all of that or maybe only one of those specific things dislodged it. Within the confines of the question's restriction to not open up the camera, that's about the best you can hope for.

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Looks like a fly! Ideal really cos it left by itself...

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    +1 – This answer is short and reads like a comment, but the size and shape of the object does look like a fly, and this would explain why it disappeared on its own. – xiota Mar 5 at 4:20
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    Welcome to Photography SE and thank you for your answer. However, I consider it very unlikely that this was a (live) fly. It was completely unimpressed by the shaking and zooming to which I subjected the camera. Also, I would have expected some hints of internal motion (breathing, cleaning) to be visible despite the fuzziness. – Wrzlprmft Mar 5 at 6:49
  • Either way, I am not exactly asking what hit my camera one-and-a-half years ago (which would be of little use to anybody, including me), but what to do if something like this happens again, which this does not really answer – unless your suggestion is to just wait. (Sidenote @xiota: The distinction between comments and answer should not be the length but the content. Comments are intended for distinctly different purposes than answers.) – Wrzlprmft Mar 5 at 6:50

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