This is actually what I’ve done so far, but it only works when afc/save_post triggers, and I’ve no live refresh of the fields either:
if (class_exists('acf')){
function taz_prefill_metadata($post_id) {
$fullImagePath = wp_get_attachment_url($post_id);
$metadata = exif_read_data($fullImagePath);
if ($metadata === false) {
exit;
} else {
$customFields = get_field_objects($post_id);
update_field($customFields['reference']['name'], (string)$metadata[FocalLength], $post_id);
}
}
}
add_action('acf/save_post', 'taz_prefill_metadata', 20); // run after ACF saves the $_POST['acf'] data
