OK, first the semantics. If a file is transferred towards the server, it is always an upload.
What permissions did you set for the FTP account? It could be the camera wants to rename files, that requires additional Delete permissions. Otherwise Write is OK.
Listing files in the directory and reading file timestamps requires List permission, also.
What permissions did you set for the FTP account? It could be the camera wants to rename files, that requires additional Delete permissions. Otherwise Write is OK.
Listing files in the directory and reading file timestamps requires List permission, also.