Quote: I wonder how much further forward the filter would need to be to render contamination out of focus?
In the pic I posted above some of the blotches were from dust on the rear lens element...or possibly even the front element as I cleaned both and they are not there now. Either way if you stop down enough they still seem to show up as blotches...probably easier to clone out the sharp dust?
Thanks for reminding me that some dust comes from wear of moving parts so hopefully I'll get less dust spots in future. It's not like I change lenses all that often! I'll see how it goes but at the moment anti dust has dived down my list of useful features to somewhere below liveview and I've never even tried to use that yet!!