5D Mk III - Black dots all over photos

[rf12790]

I just recently purchased this body off of craigslist (yep.. mistake.. i know) and after a few shoots noticed hundreds of small black dots all over my photos. I was hoping it was just dust and would be easily taken care of by a sensor cleaning, however I just had it cleaned by a professional and none of the dots have been removed. I was hoping someone could diagnose this issue and hopefully give me an opinion on what my plan of action should be. I attached a photo showing the issue.. you'll notice a large cluster up in the top right corner

Thanks!

[RobertTheFat]

How much do you know about the "professional" who cleaned it? You could have it cleaned by Canon and see if they do a better job. If they can't get the spots off, they should at least be able to tell you what they are.

[Ray-uk]

In front of the sensor is a non-removable AA filter, if there is dust on this then it will show as defocused blobs when using a wide aperture, to get  them to show as sharp dark spots then you need to use a very small aperture.

If there is actually dust on the surface of the sensor behind the AA filter then they will show as sharp dots irrespective of whatever aperture you use. It is very rare to get dust directly on the surface of the sensor and the only cure for this is usually a replacement sensor.

So try some pictures at about f5.6 and again about f22, if the spots look different then it is dust on the AA filter and can be cleaned off. If the spots look the same on both pictures then it is on the sensor and there isn't much you can do about it yourself.

As the camera was purchased used then it is possible that it may at some time have had the sensor removed and consequently dust got inside, this sort of operation can only be performed within a proper dust free environment.

[ebiggs1]

" I was hoping someone could diagnose this issue and hopefully give me an opinion on what my plan of action should be."

Your next step is to call Canon support at 1 (800) 652-2666.  Set up a C&C and sit back and take a deep breath as it will be corrected no matter what it is.  Who knows?  Let Canon figure it out.  They will go through the 5d3 and fix it.

[PaulHarwood856]

Hello Canon Community,

    I'm having the same issue. Did your problem get resolved, rf12790? Does anyone have any additional input? Any help on this would be fantastic. Thanks!

- Paul

[ebiggs1]

"Your next step is to call Canon support, too, at 1 (800) 652-2666.  Set up a C&C."