diff --git a/picamera_coverage.zip b/picamera_coverage.zip
index a29f518f..e1c41f1e 100644
Binary files a/picamera_coverage.zip and b/picamera_coverage.zip differ
diff --git a/src/openflexure_microscope_server/things/camera/__init__.py b/src/openflexure_microscope_server/things/camera/__init__.py
index 5842a2c0..049f2a29 100644
--- a/src/openflexure_microscope_server/things/camera/__init__.py
+++ b/src/openflexure_microscope_server/things/camera/__init__.py
@@ -198,6 +198,8 @@ class BaseCamera(OFMThing):
 
     def __enter__(self) -> Self:
         """Open hardware connection when the Thing context manager is opened."""
+        super().__enter__()
+
         self._background_detector_name = coerce_thing_selector(
             thing_mapping=self._all_background_detectors,
             selected=self._background_detector_name,
@@ -264,6 +266,113 @@ class BaseCamera(OFMThing):
             self.mjpeg_stream._streaming = False
             self.lores_mjpeg_stream._streaming = False
 
+    async def _monitor_framerate(
+        self,
+        duration: float,
+        sample_interval: float = 0.1,
+    ) -> tuple[float, int, list[dict[str, float | int]]]:
+        """Asynchronously monitor the timing on incoming frames."""
+        start_time = time.time()
+        last_sample_time = start_time
+        last_sample_frames = 0
+
+        frames = 0
+        samples = []
+
+        async for frame in self.mjpeg_stream.frame_async_generator():
+            if not self._framerate_monitor_running:
+                break
+
+            now = time.time()
+            frames += 1
+
+            if now - last_sample_time >= sample_interval:
+                interval = now - last_sample_time
+                fps = (frames - last_sample_frames) / interval
+
+                samples.append(
+                    {
+                        "timestamp": now,
+                        "frame_count": frames,
+                        "frame_size_bytes": len(frame),
+                        "instant_fps": fps,
+                    }
+                )
+
+                last_sample_time = now
+                last_sample_frames = frames
+
+            if now - start_time >= duration:
+                break
+
+        total_time = time.time() - start_time
+
+        return total_time, frames, samples
+
+    @lt.action
+    def record_framerate(
+        self,
+        duration: float = 5.0,
+    ) -> str:
+        """Record MJPEG stream framerate statistics."""
+        output_dir = os.path.join(
+            self.data_dir,
+            "characterisation",
+            "framerate",
+        )
+        os.makedirs(output_dir, exist_ok=True)
+
+        timestamp = time.strftime("%Y%m%d_%H%M%S")
+        datafile_path = os.path.join(
+            output_dir,
+            f"framerate_{timestamp}.json",
+        )
+
+        self.logger.info(
+            "Framerate monitor started -> %s",
+            datafile_path,
+        )
+
+        self._framerate_monitor_running = True
+
+        # This runs as an async task, which we wait to complete
+        try:
+            total_time, frames, samples = self._thing_server_interface.call_async_task(
+                self._monitor_framerate,
+                duration,
+            )
+
+        finally:
+            self._framerate_monitor_running = False
+
+        avg_fps = frames / total_time if total_time > 0 else 0
+
+        data = {
+            "summary": {
+                "total_duration": total_time,
+                "total_frames": frames,
+                "avg_fps": avg_fps,
+            },
+            "samples": samples,
+        }
+
+        self.logger.info(
+            ("Framerate monitor results: duration=%.2fs, frames=%d, avg_fps=%.2f"),
+            total_time,
+            frames,
+            avg_fps,
+        )
+
+        with open(datafile_path, "w") as f:
+            json.dump(data, f, indent=2)
+
+        self.logger.info(
+            "Framerate monitor complete -> %s",
+            datafile_path,
+        )
+
+        return datafile_path
+
     @lt.property
     def stream_active(self) -> bool:
         """Whether the MJPEG stream is active."""
diff --git a/tests/hardware_specific_tests/picamera2/cam_test_utils.py b/tests/hardware_specific_tests/picamera2/cam_test_utils.py
index 144bc54b..8a96362b 100644
--- a/tests/hardware_specific_tests/picamera2/cam_test_utils.py
+++ b/tests/hardware_specific_tests/picamera2/cam_test_utils.py
@@ -1,5 +1,6 @@
 """Utilities to help with testing the camera."""
 
+import tempfile
 from contextlib import contextmanager
 from typing import Optional
 
@@ -23,7 +24,14 @@ def camera_test_env(settings_folder: Optional[str] = None):
         "camera": StreamingPiCamera2,
         "bg_channel_deviations_luv": ChannelDeviationLUV,
     }
-    with LabThingsTestEnv(things=thing_conf, settings_folder=settings_folder) as env:
+    app_config = {
+        "data_folder": tempfile.mkdtemp(),
+    }
+    with LabThingsTestEnv(
+        things=thing_conf,
+        settings_folder=settings_folder,
+        application_config=app_config,
+    ) as env:
         yield env
 
 
diff --git a/tests/hardware_specific_tests/picamera2/test_acquisition.py b/tests/hardware_specific_tests/picamera2/test_acquisition.py
index 1d8ba1a9..7ac49e3a 100644
--- a/tests/hardware_specific_tests/picamera2/test_acquisition.py
+++ b/tests/hardware_specific_tests/picamera2/test_acquisition.py
@@ -1,5 +1,8 @@
 """Test data collection from the Raspberry Picamera."""
 
+import json
+from pathlib import Path
+
 import numpy as np
 from PIL import Image
 
@@ -29,3 +32,47 @@ def test_jpeg_and_array(picamera_client):
     # Verify image sizes are the same
     assert mjpeg_frame.size == jpeg_capture.size
     assert array_main.shape[1::-1] == jpeg_capture.size
+
+
+def test_record_framerate(picamera_client):
+    """Check that framerate monitoring creates a valid JSON log with good data."""
+    log_file = Path(picamera_client.record_framerate(duration=1.0))
+
+    assert log_file.exists()
+    assert log_file.is_file()
+
+    # Ensure file is not empty
+    assert log_file.stat().st_size > 0
+
+    # Load JSON
+    with open(log_file, "r") as f:
+        data = json.load(f)
+
+    assert "summary" in data
+    assert "samples" in data
+
+    summary = data["summary"]
+    samples = data["samples"]
+
+    assert "total_duration" in summary
+    assert "total_frames" in summary
+    assert "avg_fps" in summary
+
+    assert summary["total_duration"] > 0
+    assert summary["total_frames"] > 0
+    assert summary["avg_fps"] > 0
+
+    assert len(samples) > 0
+
+    sample = samples[0]
+
+    assert "timestamp" in sample
+    assert "frame_count" in sample
+    assert "frame_size_bytes" in sample
+    assert "instant_fps" in sample
+
+    assert sample["timestamp"] > 0
+    assert sample["frame_count"] > 0
+    assert sample["frame_size_bytes"] > 0
+
+    assert samples[-1]["frame_count"] > 0
diff --git a/tests/shared_utils/lt_test_utils.py b/tests/shared_utils/lt_test_utils.py
index 19b61723..5ceabe4c 100644
--- a/tests/shared_utils/lt_test_utils.py
+++ b/tests/shared_utils/lt_test_utils.py
@@ -42,20 +42,28 @@ class LabThingsTestEnv:
         as a context manager:
 
         :param things: The thing configuration dictionary used to initialise the server.
-        :param settings_folder: The settings folder to use.
+        :param settings_folder: The settings folder to use. If None a tempdir is created
+            for this.
+        :param application_config: The application configuration dictionary. If None is
+            supplied then "data_folder" is set to a temporary directory.
         """
         self._server: Optional[lt.ThingServer]
         self._test_client: Optional[TestClient]
         self._things_config = things
         self._settings_folder = settings_folder
         self._application_config = application_config
-        self._tmp_dir_obj: Optional[tempfile.TemporaryDirectory] = None
+        self._settings_tmp_dir: Optional[tempfile.TemporaryDirectory] = None
+        self._data_tmp_dir: Optional[tempfile.TemporaryDirectory] = None
 
     def __enter__(self) -> Self:
         """Create server and run it in the TestClient."""
+        # Any OFMThings require an application config for the data_folder
+        if self._application_config is None:
+            self._data_tmp_dir = tempfile.TemporaryDirectory()
+            self._application_config = {"data_folder": self._data_tmp_dir}
         if self._settings_folder is None:
-            self._tmp_dir_obj = tempfile.TemporaryDirectory()
-            self._settings_folder = self._tmp_dir_obj.name
+            self._settings_tmp_dir = tempfile.TemporaryDirectory()
+            self._settings_folder = self._settings_tmp_dir.name
         self._server = lt.ThingServer(
             things=self._things_config,
             settings_folder=self._settings_folder,
@@ -73,8 +81,10 @@ class LabThingsTestEnv:
     ) -> None:
         """Close the TestClient and cleanup."""
         self._test_client.__exit__(exc_type, exc_value, traceback)
-        if self._tmp_dir_obj is not None:
-            self._tmp_dir_obj.cleanup()
+        if self._settings_tmp_dir is not None:
+            self._settings_tmp_dir.cleanup()
+        if self._data_tmp_dir is not None:
+            self._data_tmp_dir.cleanup()
 
     @property
     def server(self) -> lt.ThingServer:
diff --git a/tests/unit_tests/test_simulated_camera.py b/tests/unit_tests/test_simulated_camera.py
index dd499fc9..99f486be 100644
--- a/tests/unit_tests/test_simulated_camera.py
+++ b/tests/unit_tests/test_simulated_camera.py
@@ -27,6 +27,7 @@ def test_env() -> LabThingsTestEnv:
         "stage": DummyStage,
         "bg_channel_deviations_luv": ChannelDeviationLUV,
     }
+
     with LabThingsTestEnv(things=thing_conf) as env:
         yield env