diff --git a/nion/instrumentation/MultiAcquire.py b/nion/instrumentation/MultiAcquire.py
index ae0efce..59597e3 100755
--- a/nion/instrumentation/MultiAcquire.py
+++ b/nion/instrumentation/MultiAcquire.py
@@ -690,7 +690,8 @@ def run(self, number_frames: int) -> None:
             synchronized_scan_data_stream = scan_base.make_synchronized_scan_data_stream(
                 scan_hardware_source=self.__scan_hardware_source,
                 scan_frame_parameters=copy.copy(self.scan_frame_parameters),
-                camera_hardware_source=self.__camera_hardware_source, camera_frame_parameters=camera_frame_parameters)
+                camera_hardware_source=self.__camera_hardware_source, camera_frame_parameters=camera_frame_parameters,
+                old_move_axis=True)
             synchronized_scan_data_stream = camera_base.ChannelDataStream(
                 synchronized_scan_data_stream,
                 self.camera_data_channel, Acquisition.Channel(self.__camera_hardware_source.hardware_source_id))
diff --git a/nion/instrumentation/scan_base.py b/nion/instrumentation/scan_base.py
index b827de9..6bb554a 100755
--- a/nion/instrumentation/scan_base.py
+++ b/nion/instrumentation/scan_base.py
@@ -2489,7 +2489,8 @@ def make_synchronized_scan_data_stream(
         enable_drift_tracker: bool = False,
         drift_rotation: float = 0.0,
         fov_nm_model: typing.Optional[Model.PropertyModel[float]] = None,
-        rotation_model: typing.Optional[Model.PropertyModel[float]] = None) -> Acquisition.DataStream:
+        rotation_model: typing.Optional[Model.PropertyModel[float]] = None,
+        old_move_axis: bool = False) -> Acquisition.DataStream:
 
     # there are two separate drift corrector possibilities:
     #   1 - a drift corrector that takes a separate scan, implemented using the scan_data_stream_functor
@@ -2548,6 +2549,11 @@ def make_synchronized_scan_data_stream(
         collectors.append(Acquisition.CollectedDataStream(combined_data_stream, (stop - start, scan_size.width), get_scan_calibrations(scan_frame_parameters)))
     # stack the sections together
     collector: Acquisition.DataStream = Acquisition.StackedDataStream(collectors)
+    if not old_move_axis and camera_frame_parameters.processing == "sum_masked":
+        active_masks = camera_frame_parameters.active_masks
+        if active_masks and len(active_masks) > 1:
+            collector = Acquisition.FramedDataStream(collector, operator=Acquisition.MoveAxisDataStreamOperator(
+                processed_camera_data_stream.channels[0]))
     # SynchronizedDataStream saves and restores the scan parameters; also enters/exits synchronized state
     collector = SynchronizedDataStream(collector, scan_hardware_source, camera_hardware_source, section_count)
     if scan_count > 1:
diff --git a/nion/instrumentation/test/SynchronizedAcquisition_test.py b/nion/instrumentation/test/SynchronizedAcquisition_test.py
index bacb707..f7e9154 100644
--- a/nion/instrumentation/test/SynchronizedAcquisition_test.py
+++ b/nion/instrumentation/test/SynchronizedAcquisition_test.py
@@ -301,7 +301,7 @@ def test_grab_synchronized_sum_masked_produces_data_of_correct_shape(self):
                     si_data_item = data_item
                     break
             self.assertIsNotNone(si_data_item)
-            self.assertEqual((4, 5, 3), si_data_item.data_shape)
+            self.assertEqual((3, 4, 5), si_data_item.data_shape)
 
     def test_grab_rotated_synchronized_eels(self):
         # tests whether rotation was applied, as judged by the resulting metadata
@@ -1174,8 +1174,8 @@ def test_scan_acquisition_controller_sum_masked(self):
                             break
                     self.assertIsNotNone(si_data_item)
                     if len(masks) > 1:
-                        self.assertEqual(2, si_data_item.collection_dimension_count)
-                        self.assertEqual((4, 4, len(masks)), si_data_item.data_shape)
+                        self.assertEqual(si_data_item.collection_dimension_count, 1)
+                        self.assertEqual((len(masks), 4, 4), si_data_item.data_shape)
                     else:
                         self.assertEqual(si_data_item.collection_dimension_count, 0)
                         self.assertEqual((4, 4), si_data_item.data_shape)