Anyone seen this image problem before?

MaxxuM wrote in post #3385426
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.

On this forum, I have personally been cautioned against telling people to use procedures that could harm their cameras.

Freezing is a very real problem with canned air - I realize that.

CAUTION: I do not advise using canned air - I use it but I don't recommend it for anyone else.

MaxxuM wrote in post #3385426
You know, it looks to me like bubbles formed between the filter and the sensor

They look too "3D" to be between the sensor and filter (the gap is miniscule) - these droplets have a definite "depth" to them.

Propellant on the AA filter is my guess...

Keith R wrote in post #3386407
They look too "3D" to be between the sensor and filter (the gap is miniscule) - these droplets have a definite "depth" to them.

Propellant on the AA filter is my guess...

I agree that they look three dimensional.

The 1DS Mark 2 has a FF frame sensor like the 5D, and thus I'm assuming it has the same Indium Tin Oxide filter (not glass like the xxD and pre-400D series).

This is a coating, so nothing should get between the ITO filter and the sensor unless it comes off. However the coating can come off with abrasion - but these are not abrasion marks.

But something can get "ON" the ITO filter coating.

Water drops would have evaporated by now, leaving two dimensional marks.

Assuming the spots are propellant droplets and it hasn't evaporated, hopefully they should be removable with care with a wet cleaning (Eclipse E-2 fluid).

Is there any chance that something was sprayed onto the sensor - something that could have caused bubbling of the ITO coating?

Still shooting in the dark.

Didn't the OP already state that it was cleaned? If so, if they were on the sensor then they would have looked different after the cleaning (streeks and such). Either way, if they appear with all lenses and the sensor has been cleaned that only really leaves on option - send it to canon for inspection and if need be repair.

Oh yeah, he did say that, Maxxum. Even so, logic - and the evidence in the picture - suggest that what we can see isn't liquid seeping between two surfaces.

Even if capillary action was able draw a liquid between the sensor and the AA filter, the space between is so tiny that the liquid would spread and flatten, I'd have thought.

I have no idea how well Canon UK clean sensors (or even, on the basis of this picture, whether they clean them at all!) and I can't get past the 3D appearance of these droplets, which indicates to me that they aren't constrained by hard surfaces above and beneath them.

I didn't say liquid – I think its air bubbles. True, they look too uniform to be bubbles (some should be larger than others). However, I still think its possible to get air between them, particularly if it was flash frozen + with high pressure. I agree, their effect is very 3Dish and at higher f/ noticeable. However, I doubt they would gain any 'depth' just being a nanometer higher than under the filter. I think we can agree however that it has something to do with the sensor.

Just a quick update to all of those who helped on this thread.

The camera was sent to Canon. I wasn't given a reason for the marks, but suffice to say that the sensor was replaced.

That certainly is good news for you

Best regards,
Andy

I think it looks like something like oil that has accumulated on the low pass filter from something like the shutter seals.