diff --git a/numpy_adjoint/array.py b/numpy_adjoint/array.py
index 7b824498..282101b3 100644
--- a/numpy_adjoint/array.py
+++ b/numpy_adjoint/array.py
@@ -11,7 +11,7 @@ def __init__(self, *args, **kwargs):
 
     @classmethod
     def _ad_init_object(cls, obj):
-        return cls(obj.shape, numpy.float_, buffer=obj)
+        return cls(obj.shape, obj.dtype, buffer=obj)
 
     def _ad_create_checkpoint(self):
         return self.copy()
diff --git a/tests/pyadjoint/test_numpy.py b/tests/pyadjoint/test_numpy.py
new file mode 100644
index 00000000..dc582cdc
--- /dev/null
+++ b/tests/pyadjoint/test_numpy.py
@@ -0,0 +1,10 @@
+import numpy as np
+from pyadjoint import *
+from numpy_adjoint import *
+
+
+def test_ndarray_getitem_single():
+    a = create_overloaded_object(np.array([-2.0]))
+    J = ReducedFunctional(a[0], Control(a))
+    dJ = J.derivative()
+    assert dJ == 1.0