function my_files_only( $wp_query ) {
    if ( strpos( $_SERVER[ 'REQUEST_URI' ], '/wp-admin/upload.php' ) !== false ) {
        if ( !current_user_can( 'level_5' ) ) {
            global $current_user;
            $wp_query->set( 'author', $current_user->id );
        }
    }
}

add_filter('parse_query', 'my_files_only' );

//Remove Media Library Tab
    function remove_medialibrary_tab($tabs) {
        if ( !current_user_can( 'administrator' ) ) {
            unset($tabs['library']);
            return $tabs;
        }
        else
        {
            return $tabs;
        }
    }
    add_filter('media_upload_tabs','remove_medialibrary_tab');