Thank you. I think the takeaway is - if the flash is on camera - set the unit at Zoom "A" so it meshes with the lens zoom?
- If you want flash zoomhead to have coverage area needed by the lens' set FL, set the flash to obtain its FL setting from the camera on which it is mounted (and do not use a flash manually set FL)
- If you want flash zoomhead to have coverage area needed by 'any' lens FL you choose to use -- while the flash is not under eTTL (radio/IR) control and is mounted off-camera -- set the FL of the flash manually to a Wide Angle value)
- If you have an APS-C body, you need to make sure your flash understands that FL values are based on the narrower Coverage Angle of the smaller sensor, so you may need to put your flash unit into 'APS-C' mode vs. 'FF' mode so it properly sets its flash head...camera knows '50mm', but for 50mm on APS-C the flash sets a narrower coverage angle than it would set when mounted on FF body.