Anyone seen this image problem before?

This problem can be seen in images from any of my lenses. It mostly occurs when using flash, but I have seen it occasionally in other shots. This example is enlarged from a very small portion of the original image.

It looks to me to be some sort of reflections on the sensor, as the 'bubbles' are sharp whether the area is in a focussed or defocussed area of the image.

Despite searching the web, I have yet to come up with an answer.

Someone on here must have either come across this problem, or know the answer.

Any help/ideas welcome.

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It's easy to tell if these spots are on the filter above the sensor... Take a shot of the sky at f22 and post it back here.

It almost looks as if you have condensation on the sensor or possible the back of the lens but I doubt that the back of lens would show that clearly. I am assuming that droplet looking artifact that you’re asking about.

RTMiller wrote in post #3383155
It's easy to tell if these spots are on the filter above the sensor... Take a shot of the sky at f22 and post it back here.

That would surely eliminate the lens as the culprit. Also, take the pic at ISO 100 and with the lens out of focus.

Sneezing while cleaning your sensor might result in this.

Thanks for the observations so far. As I mentioned before, this has occurred on various lenses, so I do not think that they are the culprit. Virtually all shots taken without flash do not seem to be affected.

Keep the ideas coming please.

Have you cleaned your sensor?
Have you sprayed canned compressed air in there to clean it?
Since it is a consistent problem I would guess that it is very fine oil droplets. This is a shot in the dark because we need more info.
If it were mine, I would give it a try with the copperhill method and see what happens.
As an earlier poster said, take a shot of the sky at f22. Get it into photoshop and run auto levels. If it is highly visible, it is on your sensor. Or under the filter that coveres the sensor. (hope not)

poloman wrote in post #3383800
Have you cleaned your sensor?
Have you sprayed canned compressed air in there to clean it?
Since it is a consistent problem I would guess that it is very fine oil droplets. This is a shot in the dark because we need more info.
If it were mine, I would give it a try with the copperhill method and see what happens.
As an earlier poster said, take a shot of the sky at f22. Get it into photoshop and run auto levels. If it is highly visible, it is on your sensor. Or under the filter that coveres the sensor. (hope not)

I use "Dust-Off" on a regular basis, and don't have those spots - but I never shake the can or invert it.

I keep the can on my desk, and position the camera rather than the can. The directions are quite clean - DO NOT SHAKE.

There is no oil in "Dust-Off"; the gas is cleaner than the air from a bulb blower.

Scuff:

Are the spots always in the same location on every image?

Does the 1DS M2 have a glass filter or is it a Indium Tin Oxide coating?

The sensor was cleaned recently by Canon, but the problem existed prior to that anyway.

The spots are in the same place, which suggests that they are on the AA filter. I would have expected that it would have cleared following the clean.

I have just carried out some more tests. Using flash, the spots really start to show clearly at or below f16 - F11 is OK. Without flash, I have one more stop - F16 is OK is but f22 is a definate show.

Correct me if I am wrong, but it seems that as the depth of field expands in front of the sensor and through the AA filter, the spots become sharper. This would point to something on the AA filter itself. As the sensor has been cleaned recently, maybe the stuff is sitting underneath. Maybe I will contact CPS tech next week and see if they have come across this before.

Thanks again for all of your suggestions.

Scuff wrote in post #3384281
The sensor was cleaned recently by Canon, but the problem existed prior to that anyway.

The spots are in the same place, which suggests that they are on the AA filter. I would have expected that it would have cleared following the clean.

I have just carried out some more tests. Using flash, the spots really start to show clearly at or below f16 - F11 is OK. Without flash, I have one more stop - F16 is OK is but f22 is a definate show.

Correct me if I am wrong, but it seems that as the depth of field expands in front of the sensor and through the AA filter, the spots become sharper. This would point to something on the AA filter itself. As the sensor has been cleaned recently, maybe the stuff is sitting underneath. Maybe I will contact CPS tech next week and see if they have come across this before.

Thanks again for all of your suggestions.

Based on the evidence, I agree with your conclusions.

Have you looked at the sensor with a loupe? With a good magnification, it would seem that something would be visible. I have a tiny scratch on my sensor, and it never shows up on an image until f/11 or smaller, but it's visible to the naked eye when light shines on it (the sensor filter is being replaced in late June).

Ya know, I copied it into photoshop and blew it up a bit and it looks like water spots. I wonder the cleaned it with isopropyl that contained water, like the %70 isopropyl.

gjl711 wrote in post #3384987
Ya know, I copied it into photoshop and blew it up a bit and it looks like water spots. I wonder the cleaned it with isopropyl that contained water, like the %70 isopropyl.

Apparently the spots were there before and after cleaning.

If exposed to the atmosphere, high purity alcohol will adsorb water, but then it would be pure water which shouldn't leave spots.

But as you pointed out previously, a shot with the lens out of focus would be a good test.

So far, it's still a mystery.

poloman wrote in post #3383800
Have you sprayed canned compressed air in there to clean it?

It looks like the exact thing that happened on my dads k100d after he was a little heavy handed with the canned air. Like with the OP, it only showed up when a flash was used.

Except the gunk from it was a bit stuborn and it took a few goes at cleaning the sensor to get rid of all of it.

It's a good idea to NEVER use either "canned air" (which is NOT air) or air from a typical compressor to blow out a camera.

If one gets the liquid in a can of "canned air" into the camera in liquid form, it can cause damage. There are warnings on various brands of the stuff that should be heeded.

There can be all sorts of gunk coming out of a typical home compressor. The only way that I would use a compressor to blow out a camera is to have both a high quality low-pressure regulator and a superb set of micro-fine filters (yes, that's a plural for the filters) to control and filter the air. I would also use a different hose and nozzle from my norm so that there would not be any dirt particles that could get into the air stream.

You know, it looks to me like bubbles formed between the filter and the sensor – like it had expanded then contracted (filter/film). In computers we call this flash freeze caused by using canned air too close to a microchip. Just seems logical that it would be between the two not necessarily the sensor or filter itself.

Edit: Or high preasure air got pushed between them.