Set up the Post Object field to return Post ID, then use that ID to get the field from your CPT.
// this would be somewhere in your post loop
$logo_post_id = get_field('post_object_field');
if ($logo_post_id) {
get_field('logo_image_field', $logo_post_id)
// what you do next depends on if your image field returns
// Image Array, Image URL or Image ID
}
I usually like returning Image IDs and then using wp_get_attachment_image_src() to get the image size I need rather then sorting through an array or using the URL returned by ACF so that I can determine the size used in the code.
