The role of Photographer Assistants on reconnaissance missions

As the title indicates, I’ve been looking for some clarification on what the role of the photographer’s assistants would have been on an average photo-reconnaissance mission like the ones undertaken by the 20th Combat Mapping Squadron.

I understand that all 4 gunners on the F-7A’s and F-7B’s were trained as photographer assistants, in duties such as attaching cameras to their mounts and loading and changing film roles. But it would seem that such assistance would also require one of the gun turrets to be unmanned during a mission, which doesn’t make too much sense to me.

Is it that, while trained to be assistants, in reality everything relating to the camera operation was a one man job that fell to the photographer, with the gunners being trained to lend a hand only in rare circumstances?

Any help in clarifying the jobs of all involved would be greatly appreciated.

Thanks!