New to AE - trying to use it to rescue some time lapse footage taken in very dusty conditions. Lots of sensor dust 
So far
- Exported sequence as tiff's from LR
- Imported as tiff sequence in AE
- Created "New comp from selection"
- Set the comp to 1080p24
- On the footage layer - scaled down to 46% to see all the image
- Added an adjustment layer
- Added small ellipse masks over each dust spot to the adjustment layer
- Feathered all masks to about 10px
- Applied the dust and scratches filter to the adjustment layer and set to radius 30
This looks very nice. It's worked for all 6 sequences so far.
What I want to do now is a false pan or zoom by using different parts of the image - after all - the tiff sequence is far larger than 1080p.
I tried creating a new comp - embedding the original comp as a layer and then keyframed the position and scale of the layer. This gives me the effect I want and holds the footage and adjustment layer transform in sync - but - I'm seeing poorer quality as I scale closer.
I suspect that if I applied the scaling to the original footage layer in the original comp I'd not see this degredation (in other words - instead of scaling the outer comp from 100% to 130% I reckon that I should scale the footage layer itself in the inner comp from 46% up to 80% or so). This would also be more flexible as I could move across an image with position transform rather than just scaling.
But I just can't quite see how to also scale and position the adjustment layer in sync so that the masked ellipses stay over the dust spots over time.
I'd thought I could simply manually apply the same transform to both layers - but the footage layer starts at 46% scale - the adjustment at 100% (looks like it'd work for position tho).
Would be glad if someone could point me in the right direction 