Highlight the layer. Hit the a (for Anchor) key. Change the anchor point.
Use the Pan Behind (Anchor Point) Tool (‘y” is the keyboard shortcut) to click and drag the Anchor Point to where you need it to be for your animation.
This behaves very much like moving the Anchor Point while using Free Transform in Photoshop. Also, it will retain the registration (or placement) of your layers relative to how they were stacked and aligned in Photoshop by changing both the layer Anchor Point coordinates and Position coordinates at the same time.
Assuming that you’re importing your layered Photoshop document as a Composition, the Anchor Point for each layer defaults to one of two locations:
- The center of the respective layer if imported as “Composition – Retain Layer Size”
- The center of the Photoshop document Canvas Size if imported as “Composition”
From what you’ve described, it sounds like you’re choosing as “Composition”. Although, you’ll need to use the Pan Behind (Anchor Point) Tool layer by layer regardless to achieve what you’ve going for.
There’s a behavior in AE that you could take advantage of to speed this up if you have pre-positioned your Photoshop layers such that the offset for the Anchor Point value change and the Position value change are the same for each layer. If that’s the case, you could select all the layers in After Effects and when you change the values for one layer After Effects will change the like values for all the currently selected layers as well. Since it looks like each of your layers currently has the PS Canvas Size, this might work right now.