When you activate the Auto button within the crop tool, Auto Sync functionally duplicates the calculated crop angle from the current photo across all other selected photos. This ensures they all adopt the same angle without recalculating the straighten angle for each individual photo.
For batch-straightening each selected photo independently and computing the appropriate angle for each, follow these steps:
1. Select all desired photos and navigate to the Develop module.
2. Within the Transform panel, opt for Level and Constrain Crop.
3. Utilize the Sync button and specifically choose Upright Mode.
You can also use Auto Sync, but it's inconsistent.
