diff --git a/src/wuttaweb/grids/base.py b/src/wuttaweb/grids/base.py
index 0cc8f3f..2ac2646 100644
--- a/src/wuttaweb/grids/base.py
+++ b/src/wuttaweb/grids/base.py
@@ -1404,10 +1404,11 @@ class Grid:  # pylint: disable=too-many-instance-attributes,too-many-public-meth
         Code usually does not need to call this directly.  See also
         :meth:`set_filter()`, which calls this method automatically.
 
-        :param columninfo: Can be either a model property (see below),
-           or a column name.
+        :param columninfo: Can be either a model property
+           (e.g. ``model.User.username``), or a column name
+           (e.g. ``"username"``).
 
-        :returns: A :class:`~wuttaweb.grids.filters.GridFilter`
+        :returns: :class:`~wuttaweb.grids.filters.GridFilter`
            instance.
         """
         key = kwargs.pop("key", None)
@@ -1445,12 +1446,18 @@ class Grid:  # pylint: disable=too-many-instance-attributes,too-many-public-meth
 
         :param key: Name of column.
 
-        :param filterinfo: Can be either a
-           :class:`~wuttweb.grids.filters.GridFilter` instance, or
-           else a model property (see below).
+        :param filterinfo: Can be either a filter factory, or else a
+           model property (e.g. ``model.User.username``) or column
+           name (e.g. ``"username"``).  If not specified then the
+           ``key`` will be used instead.
 
-        If ``filterinfo`` is a ``GridFilter`` instance, it will be
-        used as-is for the backend filter.
+        :param \\**kwargs: Additional kwargs to pass along to the
+           filter factory.
+
+        If ``filterinfo`` is a factory, it will be called with the
+        current request, key and kwargs like so::
+
+           filtr = factory(self.request, key, **kwargs)
 
         Otherwise :meth:`make_filter()` will be called to obtain the
         backend filter.  The ``filterinfo`` will be passed along to
@@ -1462,12 +1469,13 @@ class Grid:  # pylint: disable=too-many-instance-attributes,too-many-public-meth
         filtr = None
 
         if filterinfo and callable(filterinfo):
-            # filtr = filterinfo
-            raise NotImplementedError
+            kwargs.setdefault("label", self.get_filter_label(key))
+            filtr = filterinfo(self.request, key, **kwargs)
 
-        kwargs["key"] = key
-        kwargs.setdefault("label", self.get_label(key))
-        filtr = self.make_filter(filterinfo or key, **kwargs)
+        else:
+            kwargs["key"] = key
+            kwargs.setdefault("label", self.get_filter_label(key))
+            filtr = self.make_filter(filterinfo or key, **kwargs)
 
         self.filters[key] = filtr
 
diff --git a/tests/grids/test_base.py b/tests/grids/test_base.py
index 3dd8208..1e193ea 100644
--- a/tests/grids/test_base.py
+++ b/tests/grids/test_base.py
@@ -1310,10 +1310,13 @@ class TestGrid(WebTestCase):
             grid.set_filter("name")
             self.assertIn("name", grid.filters)
 
-            # explicit is not yet implemented
+            # auto from filter factory
             grid = self.make_grid(model_class=model.Setting)
             self.assertEqual(grid.filters, {})
-            self.assertRaises(NotImplementedError, grid.set_filter, "name", lambda q: q)
+            grid.set_filter(
+                "name", StringAlchemyFilter, model_property=model.Setting.name
+            )
+            self.assertIn("name", grid.filters)
 
     def test_remove_filter(self):
         model = self.app.model