Originally posted by AndyNick What do you think? Has something alien taken up residence on my sensor and can't be evicted with the sensor cleaner? Or is it a sign of the string appearing after some heated usage? Look forward to hearing your thoughts.
Originally posted by falconeye it will be early next week as I'm too busy right now.
Ok, I now had a closer look.
The numerical evaluation wasn't exactly as precise as in the earlier case. I looked at a smaller and a larger stain in particular, at various f-stops.
The smaller stain (lower left) seems to be about 30-50µm and from the sensor cover glass. The larger stain (upper right) seems to be about 40-60µm and from anywhere below the AA filter (there's some variation but cover glass is a good possibility too).
The stains seem to have minimal optical properties, e.g., arent't exact dark disks. But they are similiar enough that I call them samples of the string of pearls. The differences are within the variations we've seen so far from other cameras with the same effect too.
So, we have one confirmed case where the string of pearls developped after the camera shipped.
I leave it to the forum to decide if Pentax should be informed about...