Looking at your comment, photos and videos aren’t custom post types but actually categories. I’m changing my answer to reflect your comment.
You can use pre_get_posts
to exclude specific categories in your loop. You can achieve that with $query->set( 'cat=-1,-2,-3' );
This will exclude categories with ID’s 1, 2 and 3, and will only show categories with ID’s other that 1, 2 and 3.
Just remember, to exclude categories, you have to use the minus(-) sign in front of the category ID.
Here is the complete code that should go into your functions.php to exclude your categories on your taxonomy page
function exclude_category( $query ) {
if ( !is_admin() && $query->is_tax() && $query->is_main_query() ) {
$query->set( 'cat', '-1,-2,-3' );
}
}
add_action( 'pre_get_posts', 'exclude_category' );