Index: django/template/defaultfilters.py
===================================================================
--- django/template/defaultfilters.py	(revision 7178)
+++ django/template/defaultfilters.py	(working copy)
@@ -619,8 +619,10 @@
     from django.utils.dateformat import format
     if not value:
         return u''
-    if arg is None:
+    if arg in [None, 'x']:
         arg = settings.DATE_FORMAT
+    elif arg == 'X':
+        arg = settings.DATETIME_FORMAT
     return format(value, arg)
 date.is_safe = False