While it is customary for photographers to clean their cameras every so often to remove dust on the lens and such, it looks like if you were thinking of picking up the Nikon D600, you might have to do more than just blow air on the sensor to clean it. According to multiple reports, it seems that simply by blowing air on the sensor was not good enough to remove the dust on it. Instead it seems that some photographers had to perform a wet clean. Granted this isn’t that big of a deal, nor is it a deal breaker, but it might be inconvenient out in the field.
According to the folks at dpreview who reviewed the camera:
“An issue that has been reported widely on the web concerns the unusual frequency with which the D600 attracts dust and/or residue on its sensor, particularly in the upper left area of an image, which of course corresponds to the bottom right portion of the actual sensor. And sure enough, shortly after we received our review sample and began our studio testing we found we had to conduct a rudimentary non-invasive sensor cleaning.
We can only speculate at this point as to the cause of the issue. What we can say is that simply blowing air did not remove all of the debris; a wet clean was required, suggesting that some contaminant may have found its way onto the sensor. We are of course, pursuing this issue with Nikon directly, and will update this review as more information comes to light.”
It seems that the cause of this issue might be due to the shutter curtain opening on the D600 was larger compared to other Nikon cameras with a slight gap, which could explain how dust gets pulled onto the sensor and seemingly always landing in the same spot. However as Nikon Rumors noted, the D800 was faced with similar issues which was then resolved with later shipments of the camera, so perhaps you might want to wait it out a bit before getting your hands on it.