D600 sensor splotches

My D600 sensor has three splotches visible at F32. They are quite large, maybe 3-5mm wide, and round. Now my understanding is that

small apertures produce highly collimated light, which creates well defined edges for dirt on the filter plate. Hence F32 highlights dirt. I

had never wet cleaned the sensor before I saw them. Two wet cleanings have not removed the splotches. Fortunately they do not appear

at F16, which is the aperture I use the most, but I do a lot of macro photography so it can be an issue.

 

So, does anyone know where the contaminant has come from? And what it is? The sensor does get a lot of dust in use, but I do use live

view a lot, especially with a microscope, so dirt ingress is to he expected. I dry cleaned the sensor, shot off 100 shots, and found no

increase in dirt, so I don't think this is the notorious D600 shutter gubbins issue. I can only think the marks were there from new.

<p>It's possible that it could be something trapped under the low pass filter. If that's the case I think only Nikon could deal with it.</p>

<p>I'd still first try to locate the origin better to remove the symptoms more effectively. Are you are absolutely sure that those splotches are on the sensor and not on some other part of the optical system?<br>

A test image with setup like when you get those blobs, but keep the lens in a different rotation position by a hand or similar arrangement?<br>

Wet cleaning, what type of? There are basically two types of wet cleaning liquides. One type is more suitable for dust etc. and an another type is more suitable for grease.</p>

<p>At 3-5 mm they certainly are visible to the naked eye. I suspect they might not be on the sensor. Do you see these in live view? If so, you have limited the smudges to the sensor or the lens. Some lenses can produce anomalies, especially at close-up ranges.</p>