We tend not to get too excited about sensor dust problems at LensRentals; we clean sensors on every camera after every rental, so it’s just routine. When we started carrying the Nikon D600, they all arrived with a fair amount of dust, but that’s pretty routine, too. Manufacturing and shipping can be a dusty experience.
But the dust kept reappearing with every rental, and, more impressively, it was generally in the same location (in the upper-left 1/3 of the image). That did get our attention, so we started looking into the matter a bit. We kept dust pictures for 20 consecutive D600s returning from rental and saw that the problem was very real.
In general, about 1 out of 4 cameras requires sensor cleaning after a rental. All 20 of the D600s did.
Here are a few typical examples (f/16 photos of a blank wall with contrast and exposure increased). I would point out that these are downsized to 800-pixel wide images. What is barely-visible dust on this is quite obvious on a full-size image. The large specs on this are quite huge at full size.
It’s probably pretty apparent that the dust is mostly on the left side of the image. I took all 20 images and layered them onto one in Photoshop, using ‘darken if’ to show the pattern of dust from 20 cameras:
Again, with these downsized images, only the really large dust specs are showing up, but then again, those are the ones most likely to show up in a photo. I would also add that these almost all seem to be dust specs, not oil, since most of them can be blown off or stamped off using a Dust-Aid. They don’t require wet cleaning to remove as oil spots do.
There have been, however, a number of comments from experienced photographers who are having oil spots on their D600s. I’m not sure whether they’re seeing the same phenomenon as we are, or a different one.
We aren’t absolutely certain about the cause, but when we have to look at the sensors for all this cleaning one thing is quite apparent. The D600′s shutter curtain opening seems to be a bit larger than the other Nikon cameras, with a bit of a gap around the shutter curtain.
It may well be that the shutter movement is pulling dust onto the sensor.
The real question is: Will the dust eventually stop accumulating on the sensor? I think probably so. There’s some dust inside the camera that is getting blown out during early use through the shutter opening. But that’s just an educated guess; only time will tell.
For now, though, we suggest looking fairly frequently for dust accumulation.
P.S. All of these cameras were from SN 300xxxx or 301xxxx. We have another 40 D600s but since they, too, are from these SN runs I don’t plan any further comparisons. We’ll check again when we get higher SNs.