Hello All
I was clicking away at the rainbow the other night and noticed that on one shot there was a rash of what appeared to be sensor dust:
I took the next one and no dust:
The difference is that the second one has been processed as I liked it etc ....but originally no dust while the first pic is splattered. The only differences between them
dirty: f22 1/80
clean: f/4 1/125
Would closing the lens to f/22 somehow do this?
No idea!
Yes, I think so. I have experienced the same problems myself.
and you also have SonyA7rii is it? it cant be dust on sensor can it
I had the problem on my old Panasonic, the sensor dirt could not be removed hence the move to Sony A7iii
I’m afraid it probably is sensor dust. Stopping down would make it worse. I think this is because the dust is not on the sensor itself but on the hot mirror filter that sits on top of the sensor so it’s not on the same focal plane.
If you want to visualise the dust, the best way is to take an out-of-focus picture of a blank sky or white sheet of paper. Turn to manual focus for this and use a small aperture. Get the image into Photoshop and go to Levels. Click on the Auto button. This will force contrast into the image and show up all the dust. You may be alarmed by what you see, but this is a good way of checking how effective any cleaning attempts have been.
I have had the same problems when photographing the sky at a small aperture. I have often found the dust appears when converted to monochrome as well, even if you cannot see it in the colour raw or processed files.
Thanks for the tip Diddy D!