diff --git a/nifty5/operators/simple_linear_operators.py b/nifty5/operators/simple_linear_operators.py
index 4cae72cfbed4714247d5d9578bf4e27fef499370..a32c6978ce39f7552270ffd2319d3a5eca573298 100644
--- a/nifty5/operators/simple_linear_operators.py
+++ b/nifty5/operators/simple_linear_operators.py
@@ -150,7 +150,7 @@ class _SlowFieldAdapter(LinearOperator):
         if isinstance(x, MultiField):
             return x[self._name]
         else:
-            return MultiField.from_dict(self._tgt(mode), {self._name: x})
+            return MultiField.from_dict({self._name: x}, domain=self._tgt(mode))
 
     def __repr__(self):
         return '_SlowFieldAdapter'