Author Page Custom Query WHERE author OR [post meta value] OR [post meta value]

For anyone who may have a similar need, I solved this the following way (on authors.php):

First I get the author ID:

$author = get_user_by( 'slug', get_query_var( 'author_name' ) );

// ID is accessed this way:
$author_id = $author->ID;

I then created a custom query:

        $query = "
                SELECT p.* 
                FROM   $wpdb->postmeta m 
                             JOIN $wpdb->posts p 
                                 ON p.id = m.post_id 
                WHERE  ( m.meta_key = 'medium_post_photographers' 
                                 AND m.meta_value="$author->ID" ) 
                                OR ( m.meta_key = 'medium_post_videographers' 
                                         AND m.meta_value="$author->ID" ) 
                                     AND p.post_status="publish" 
                UNION DISTINCT 
                SELECT * 
                FROM   $wpdb->posts p 
                WHERE  post_author = $author->ID 
                             AND p.post_status="publish" 
                GROUP  BY p.id 
                ORDER  BY post_date DESC 
        ";

And finally use the following to get the results:

 $author_posts = $wpdb->get_results($query, OBJECT);   

Here is a simplified version of my loop to display the results:

<?php if ( $author_posts ) : ?>
    <?php global $post; ?>
    <?php foreach ( $author_posts as $post ) : setup_postdata($post); ?>
        <h6><?php echo the_title(); ?></h6>
        ...
    <?php endforeach; ?>
<?php else: ?>
    <div class="alert">There are no posts in this category.</div>
<?php endif; ?>

I hope this helps someone!