diff --git a/nifty5/energies/hamiltonian.py b/nifty5/energies/hamiltonian.py
index cdf2dc44c65d78e7d30f30d177ff89be4022963f..741c4b1328b9c67622e52c37a1e740dd895e19ad 100644
--- a/nifty5/energies/hamiltonian.py
+++ b/nifty5/energies/hamiltonian.py
@@ -54,11 +54,11 @@ class Hamiltonian(Energy):
     @memo
     def curvature(self):
         prior_curv = self._prior.curvature
-        if self._ic_samp is not None:
+        if self._ic_samp is None:
+            c = self._lh.curvature + prior_curv
+        else:
             c = SamplingEnabler(self._lh.curvature, prior_curv.inverse,
                                 self._ic_samp, prior_curv.inverse)
-        else:
-            c = self._lh.curvature + prior_curv
         return InversionEnabler(c, self._ic, self._precond)
 
     def __str__(self):