diff --git a/src/openflexure_microscope_server/things/autofocus.py b/src/openflexure_microscope_server/things/autofocus.py
index 4e966d27..f833ba53 100644
--- a/src/openflexure_microscope_server/things/autofocus.py
+++ b/src/openflexure_microscope_server/things/autofocus.py
@@ -26,6 +26,7 @@ from pydantic import BaseModel
 
 Stage = direct_thing_client_dependency(SangaboardThing, "/stage/")
 Camera = raw_thing_dependency(StreamingPiCamera2)
+WrappedCamera = direct_thing_client_dependency(StreamingPiCamera2, "/camera/")
 
 ### Autofocus utilities
 
@@ -206,12 +207,14 @@ class AutofocusThing(Thing):
         """
         repeat = True
         attempts = 0
+        backlash = 200
 
         with m.run():
             while repeat and attempts < 10:
 
                 if start == 'centre':
-                    stage.move_relative(x = 0, y = 0, z = -dz / 2)
+                    stage.move_relative(x = 0, y = 0, z = -(backlash + dz / 2))
+                    stage.move_relative(x = 0, y = 0, z = backlash)
 
                 i, z = m.focus_rel(dz, block_cancellation=True)
                 _, heights, sizes = m.move_data(i)
@@ -226,8 +229,24 @@ class AutofocusThing(Thing):
                 ):
                     attempts += 1
                     start = 'centre'
+                    stage.move_absolute(z = peak_height-backlash)
                     stage.move_absolute(z = peak_height)
                 else:
                     repeat = False
-                    stage.move_relative(x = 0, y = 0, z = -dz)
-                    stage.move_absolute(z = peak_height)
\ No newline at end of file
+                    stage.move_relative(x = 0, y = 0, z = -(dz+backlash))
+                    stage.move_absolute(z = peak_height)
+            return heights.tolist(), sizes.tolist()
+
+    @thing_action
+    def verify_focus_sharpness(self, sweep_sizes: list, camera: WrappedCamera, leniency: int = 1):
+        '''Take the sharpness curve of the autofocus, and the size of the current frame
+        to see if the autofocus completed successfully. Returns True if current sharpness
+        is within "leniency" number of frames from the peak of the autofocus'''
+
+        current_sharpness = camera.grab_jpeg_size(stream_name='lores')
+
+        peak = np.argmax(sweep_sizes)
+        accepted_range = [peak - leniency, peak + leniency]
+
+        sharpness_range = [sweep_sizes[i] for i in accepted_range]
+        return current_sharpness >= min(sharpness_range)
\ No newline at end of file
diff --git a/src/openflexure_microscope_server/things/smart_scan.py b/src/openflexure_microscope_server/things/smart_scan.py
index b03c2d93..2c38c7a6 100644
--- a/src/openflexure_microscope_server/things/smart_scan.py
+++ b/src/openflexure_microscope_server/things/smart_scan.py
@@ -640,24 +640,29 @@ class SmartScanThing(Thing):
                     attempts = 0
                     if self.autofocus_dz > 200:
                         while True:
-                            autofocus.looping_autofocus(dz=self.autofocus_dz, start = 'base')
+                            jpeg_zs, jpeg_sizes = autofocus.looping_autofocus(dz=self.autofocus_dz, start = 'base')
                             current_height = stage.position["z"]
+                            autofocus_success = autofocus.verify_focus_sharpness(sweep_sizes = jpeg_sizes, camera = CamDep, leniency = 1)
+                            logger.info(f"We just tested the focus! Result was {autofocus_success}")
 
-                            # if there have been successful autofocuses in this scan, find the closest one in x-y
-                            # test if the change in z between them exceeds a ratio (indicating a failed autofocus)
-                            if len(focused_path) > 0:
-                                nearest_focused_site = focused_path[closest(loc, focused_path)]
-                                result = limit_focus_change(
-                                    nearest_focused_site[0:2],
-                                    nearest_focused_site[-1],
-                                    loc[0:2],
-                                    current_height,
-                                    0.3,
-                                )
+                            if autofocus_success:
+                                # if there have been successful autofocuses in this scan, find the closest one in x-y
+                                # test if the change in z between them exceeds a ratio (indicating a failed autofocus)
+                                if len(focused_path) > 0:
+                                    nearest_focused_site = focused_path[closest(loc, focused_path)]
+                                    result = limit_focus_change(
+                                        nearest_focused_site[0:2],
+                                        nearest_focused_site[-1],
+                                        loc[0:2],
+                                        current_height,
+                                        0.3,
+                                    )
 
-                            # if there haven't been any previous autofocuses, we have to assume this one worked
+                                # if there haven't been any previous autofocuses, we have to assume this one worked
+                                else:
+                                    result = "accept"
                             else:
-                                result = "accept"
+                                result = "reject"
 
                             # if the autofocus worked, add the current position to the list of successful locations
                             if result == "accept":
@@ -762,6 +767,15 @@ class SmartScanThing(Thing):
     def max_range(self, value: int) -> None:
         self.thing_settings["max_range"] = value
 
+    @thing_property
+    def stitch_tiff(self) -> bool:
+        """The maximum distance from the centre of the scan before we break"""
+        return self.thing_settings.get("stitch_tiff", False)
+
+    @stitch_tiff.setter
+    def stitch_tiff(self, value: bool) -> None:
+        self.thing_settings["stitch_tiff"] = value
+
     @thing_property
     def skip_background(self) -> bool:
         """Whether to detect and skip empty fields of view