I was confused by the term priest as I have only heard of that used for Catholic priests, but the actual definition is more open than that.
The officiant was wrong. It should have been addressed prior to the ceremony if it was that big of a deal to him. The camera people seemed polite and were asked where they should stand, so I assume they were not told beforehand not to be there.
At our rehearsal the night before, the Deacon asked the flower girls to please not play on the altar, my husband then asked about the photographer and where she was allowed during the ceremony. The Deacon said that she could be anywhere she wanted as long as she wasn't directly in the way or tripping people.
This was a big Catholic wedding in a large older church and she was at times behind the officiant but was always as inconspicuous as possible. I was glad that we asked, as I don't know that I would have assumed that was okay. I think in a church it seems more like you are in the clergy's home or space, whereas an outdoor ceremony where the couple set up the place, etc it seems less likely that the officiant would have an issue.
But if it was NOT okay, esp in a non-church wedding, the officiant should have brought it up beforehand and not just expected people to know. (once again, I am assuming it wasn't discussed as the camera people were asking where was allowed during the video.)