is there a way to retrieve posts that do not have a featured image assigned?

by 

$mediaargs = array(
        'post_type' => 'media',
        'posts_per_page' => 1,
        'paged' => $paged,
        'order' => 'DESC',
        'orderby' => 'modified',
        'meta_query' => array(
            array(
                'key' => '_thumbnail_id',
                'compare' => 'NOT EXISTS'
            )
        ),
    );