diff --git a/monai/transforms/intensity/array.py b/monai/transforms/intensity/array.py
index a1423c8ee5..a8babfc659 100644
--- a/monai/transforms/intensity/array.py
+++ b/monai/transforms/intensity/array.py
@@ -955,7 +955,7 @@ def __init__(self, window_length: int, order: int, axis: int = 1, mode: str = "z
         self.mode = mode
         self.img_t: torch.Tensor = torch.tensor(0.0)
 
-    def __call__(self, img: NdarrayOrTensor) -> torch.Tensor:
+    def __call__(self, img: NdarrayOrTensor) -> NdarrayOrTensor:
         """
         Args:
             img: array containing input data. Must be real and in shape [channels, spatial1, spatial2, ...].
@@ -969,7 +969,9 @@ def __call__(self, img: NdarrayOrTensor) -> torch.Tensor:
         # add one to transform axis because a batch axis will be added at dimension 0
         savgol_filter = SavitzkyGolayFilter(self.window_length, self.order, self.axis + 1, self.mode)
         # convert to Tensor and add Batch axis expected by HilbertTransform
-        out: torch.Tensor = savgol_filter(self.img_t.unsqueeze(0)).squeeze(0)
+        smoothed = savgol_filter(self.img_t.unsqueeze(0)).squeeze(0)
+        out, *_ = convert_to_dst_type(smoothed, dst=img)
+
         return out
 
 
diff --git a/monai/transforms/spatial/array.py b/monai/transforms/spatial/array.py
index df3d3eb093..1b03d39a15 100644
--- a/monai/transforms/spatial/array.py
+++ b/monai/transforms/spatial/array.py
@@ -571,7 +571,7 @@ class Zoom(Transform):
 
     """
 
-    backend = [TransformBackends.TORCH, TransformBackends.NUMPY]
+    backend = [TransformBackends.TORCH]
 
     def __init__(
         self,
diff --git a/tests/test_savitzky_golay_smooth.py b/tests/test_savitzky_golay_smooth.py
index 45d0ea3e4d..71405466c4 100644
--- a/tests/test_savitzky_golay_smooth.py
+++ b/tests/test_savitzky_golay_smooth.py
@@ -62,7 +62,7 @@ class TestSavitzkyGolaySmooth(unittest.TestCase):
     @parameterized.expand([TEST_CASE_SINGLE_VALUE, TEST_CASE_2D_AXIS_2, TEST_CASE_SINE_SMOOTH])
     def test_value(self, arguments, image, expected_data, atol):
         for p in TEST_NDARRAYS:
-            result = SavitzkyGolaySmooth(**arguments)(p(image))
+            result = SavitzkyGolaySmooth(**arguments)(p(image.astype(np.float32)))
             torch.testing.assert_allclose(result, p(expected_data.astype(np.float32)), rtol=1e-7, atol=atol)
 
 
@@ -70,7 +70,7 @@ class TestSavitzkyGolaySmoothREP(unittest.TestCase):
     @parameterized.expand([TEST_CASE_SINGLE_VALUE_REP])
     def test_value(self, arguments, image, expected_data, atol):
         for p in TEST_NDARRAYS:
-            result = SavitzkyGolaySmooth(**arguments)(p(image))
+            result = SavitzkyGolaySmooth(**arguments)(p(image.astype(np.float32)))
             torch.testing.assert_allclose(result, p(expected_data.astype(np.float32)), rtol=1e-7, atol=atol)