diff --git a/apps/ctt-server/ctt_server/app.py b/apps/ctt-server/ctt_server/app.py
index 1237db0..0462074 100644
--- a/apps/ctt-server/ctt_server/app.py
+++ b/apps/ctt-server/ctt_server/app.py
@@ -34,6 +34,7 @@
     MJPEG_CONTENT_TYPE,
     CameraError,
     get_shared_camera,
+    list_cameras,
     platform_target,
     reload_shared_camera,
 )
@@ -239,7 +240,30 @@ def images_page(name: str):
     @app.route('/api/health')
     def api_health():
         try:
-            return jsonify({'camera': True, **get_shared_camera().health()})
+            cam = get_shared_camera()
+            return jsonify({
+                'camera': True,
+                'cameras': list_cameras(),
+                **cam.health(),
+            })
+        except CameraError as err:
+            return jsonify({'camera': False, 'error': str(err)}), 503
+
+    @app.route('/api/cameras')
+    def api_cameras():
+        return jsonify(list_cameras())
+
+    @app.route('/api/camera', methods=['POST'])
+    def api_switch_camera():
+        """Switch to a different camera by its index number."""
+        body = request.get_json(force=True) or {}
+        try:
+            camera_num = int(body['camera_num'])
+        except (KeyError, TypeError, ValueError):
+            return jsonify({'error': 'camera_num (int) is required'}), 400
+        try:
+            cam = get_shared_camera(camera_num=camera_num)
+            return jsonify({'camera': True, **cam.health()})
         except CameraError as err:
             return jsonify({'camera': False, 'error': str(err)}), 503
 
diff --git a/apps/ctt-server/ctt_server/camera.py b/apps/ctt-server/ctt_server/camera.py
index 4ba7e37..a16c458 100644
--- a/apps/ctt-server/ctt_server/camera.py
+++ b/apps/ctt-server/ctt_server/camera.py
@@ -50,7 +50,9 @@ class Picamera2Camera:
     viewfinder's field of view is exactly what the captured DNG covers.
     """
 
-    def __init__(self, preview_max_width: int = 1920, tuning_file: str | None = None) -> None:
+    def __init__(
+        self, preview_max_width: int = 1920, tuning_file: str | None = None, camera_num: int = 0
+    ) -> None:
         try:
             from picamera2 import Picamera2  # noqa: PLC0415 (lazy import)
         except ImportError as err:  # pragma: no cover - depends on Pi environment
@@ -64,19 +66,20 @@ def __init__(self, preview_max_width: int = 1920, tuning_file: str | None = None
             Picamera2.set_logging(logging.WARNING)  # quieten Picamera2's own INFO chatter (once)
             _picamera2_logging_quieted = True
 
+        self.camera_num = camera_num
         self._lock = threading.Lock()
         self._ev = 0.0  # exposure compensation (EV); tracked here as metadata may omit it
         self._auto = True  # AeEnable state; tracked so we report it reliably (AeLocked is ambiguous)
-        self._fps = 30.0  # framerate target; 0 = unconstrained (variable frame duration)
+        self._fps = 0.0  # framerate target; 0 = unconstrained — set by _apply_mode or user
         # Optionally start the pipeline with a specific tuning file (e.g. a freshly
         # generated CTT tuning, for the Results-page live preview test). None = the
         # camera's built-in default tuning.
         self.tuning_file = tuning_file
         if tuning_file:
             tuning = Picamera2.load_tuning_file(os.path.basename(tuning_file), dir=os.path.dirname(tuning_file))
-            self._picam2 = Picamera2(tuning=tuning)
+            self._picam2 = Picamera2(tuning=tuning, camera_num=camera_num)
         else:
-            self._picam2 = Picamera2()
+            self._picam2 = Picamera2(camera_num=camera_num)
         try:
             self.model = self._picam2.camera_properties.get('Model', 'unknown')
             # Advertised sensor modes, one entry per raw size (preferring the deeper
@@ -133,6 +136,11 @@ def _apply_mode(self, mode: dict) -> None:
         prev_w = min(self._preview_max_width, w) & ~1
         prev_h = int(round(prev_w * h / w)) & ~1
         self._preview_size = (prev_w, prev_h)
+        # Adopt the mode's maximum framerate so the user starts at the best
+        # rate for the new resolution, not a stale target from a prior mode.
+        mode_fps = mode.get('fps', 0)
+        if mode_fps:
+            self._fps = mode_fps
 
     def _sensor_config(self) -> dict:
         # sensor= pins the actual camera mode (readout/binning) so libcamera
@@ -479,6 +487,7 @@ def capture_burst(self, frames: int, quality: int = 95) -> list[tuple[bytes, byt
 
     def health(self) -> dict:
         return {
+            'camera_num': self.camera_num,
             'model': self.model,
             'resolution': list(self.resolution),
             'modes': [
@@ -504,13 +513,22 @@ def close(self) -> None:
 _SHARED_LOCK = threading.Lock()
 
 
-def get_shared_camera() -> Picamera2Camera:
-    """Return a process-wide singleton camera (one Picamera2 per process)."""
+def get_shared_camera(camera_num: int | None = None) -> Picamera2Camera:
+    """Return a process-wide singleton camera (one Picamera2 per process).
+
+    When *camera_num* is given and differs from the currently open camera, the
+    current camera is closed and reopened on the requested index.  When
+    *camera_num* is None the current camera is returned unchanged (or the first
+    available camera on the first call).
+    """
     global _SHARED
     with _SHARED_LOCK:
+        if camera_num is not None and _SHARED is not None and _SHARED.camera_num != camera_num:
+            _SHARED.close()
+            _SHARED = None
         if _SHARED is None:
             try:
-                _SHARED = Picamera2Camera()
+                _SHARED = Picamera2Camera(camera_num=camera_num or 0)
             except CameraError:
                 raise
             except Exception as err:
@@ -518,6 +536,28 @@ def get_shared_camera() -> Picamera2Camera:
         return _SHARED
 
 
+def list_cameras() -> list[dict]:
+    """Return every camera detected by libcamera on this Pi.
+
+    Each entry has ``num``, ``model``, ``id``, ``location`` and ``rotation``
+    fields, suitable for the UI camera selector.
+    """
+    try:
+        from picamera2 import Picamera2  # noqa: PLC0415
+    except ImportError:
+        return []
+    return [
+        {
+            'num': c['Num'],
+            'model': c.get('Model', 'unknown'),
+            'id': c.get('Id', ''),
+            'location': c.get('Location', 0),
+            'rotation': c.get('Rotation', 0),
+        }
+        for c in Picamera2.global_camera_info()
+    ]
+
+
 def validate_tuning_file(path: str, timeout: float = 60.0) -> None:
     """Test-load a tuning file by bringing the camera up in a throwaway subprocess.
 
@@ -559,7 +599,8 @@ def validate_tuning_file(path: str, timeout: float = 60.0) -> None:
 
 
 def reload_shared_camera(
-    tuning_file: str | None = None, preview_max_width: int = 1920, validate: bool = False
+    tuning_file: str | None = None, preview_max_width: int = 1920,
+    validate: bool = False, camera_num: int | None = None,
 ) -> Picamera2Camera:
     """Restart the shared camera with a given tuning file (None = default tuning).
 
@@ -568,24 +609,34 @@ def reload_shared_camera(
     capture page's "restore default" call cheap. validate=True canary-tests the
     tuning in a subprocess first (see validate_tuning_file) — use it for any
     tuning that isn't known-good, e.g. hand-edited custom files.
+
+    When *camera_num* is given, also switches to that camera index.
     """
     global _SHARED
     with _SHARED_LOCK:
+        if camera_num is not None and _SHARED is not None and _SHARED.camera_num != camera_num:
+            _SHARED.close()
+            _SHARED = None
         if _SHARED is not None and _SHARED.tuning_file == tuning_file:
             return _SHARED
         if _SHARED is not None:
             _SHARED.close()
             _SHARED = None
+        target_num = camera_num if camera_num is not None else 0
         try:
             if validate and tuning_file is not None:
                 validate_tuning_file(tuning_file)
-            _SHARED = Picamera2Camera(preview_max_width=preview_max_width, tuning_file=tuning_file)
+            _SHARED = Picamera2Camera(
+                preview_max_width=preview_max_width, tuning_file=tuning_file, camera_num=target_num,
+            )
         except Exception as err:
             # The requested tuning failed to load: reopen with the default
             # tuning so the camera isn't left dead, then report.
             if tuning_file is not None:
                 with contextlib.suppress(Exception):
-                    _SHARED = Picamera2Camera(preview_max_width=preview_max_width)
+                    _SHARED = Picamera2Camera(
+                        preview_max_width=preview_max_width, camera_num=target_num,
+                    )
             if isinstance(err, CameraError):
                 raise
             tuning_name = os.path.basename(tuning_file) if tuning_file else 'the default tuning'
diff --git a/apps/ctt-server/ctt_server/static/app.css b/apps/ctt-server/ctt_server/static/app.css
index c45f135..40b8ba5 100644
--- a/apps/ctt-server/ctt_server/static/app.css
+++ b/apps/ctt-server/ctt_server/static/app.css
@@ -430,4 +430,4 @@ td.mono { font-family: var(--mono); }
 }
 
 /* sensor-mode dropdown in the preview info box */
-.caminfo .mode-sel { width: auto; padding: 3px 8px; font-size: 0.85rem; align-self: flex-start; }
+.caminfo .mode-sel { width: auto; max-width: 100%; padding: 3px 8px; font-size: 0.85rem; align-self: flex-start; }
diff --git a/apps/ctt-server/ctt_server/static/app.js b/apps/ctt-server/ctt_server/static/app.js
index 2a3ca72..a04bfb5 100644
--- a/apps/ctt-server/ctt_server/static/app.js
+++ b/apps/ctt-server/ctt_server/static/app.js
@@ -168,8 +168,8 @@ function captureApp(cfg) {
     counts: { macbeth: 0, alsc: 0, cac: 0, dark: 0 },
     form: { image_type: 'macbeth', colour_temp: 6500, lux: 1000, frames: 1 },
     controls: { exposure: 10000, gain: 1.0, auto_exposure: true, colour_temp: 0, lux: 0, ev: 0 },
-    fpsTarget: 30,  // framerate target; 0 = unconstrained (variable frame duration)
-    camera: { model: '', resolution: null },
+    fpsTarget: 0,  // framerate target; 0 = unconstrained — set by loadControls or user
+    camera: { model: '', resolution: null, modes: [] },
     metered: { exposure: 0, gain: 0, colour_temp: 0, lux: 0, focus_fom: 0 },
     clip: { r: 0, g: 0, b: 0 },
     macbeth: { found: false, confidence: null, corners: null, small: false, saturated: false },
@@ -179,6 +179,8 @@ function captureApp(cfg) {
     hflip: false,
     vflip: false,
     previewTick: 0,  // bumped to reconnect the MJPEG <img> after a camera reconfigure
+    cameras: [],     // list of all cameras detected on the server
+    cameraNum: 0,    // currently selected camera index
 
     async init() {
       this.updateCounts();
@@ -189,8 +191,11 @@ function captureApp(cfg) {
         const r = await fetch('/api/health');
         const h = await r.json();
         this.connected = !!h.camera;
+        if (h.cameras) this.cameras = h.cameras;
+        this.cameraNum = h.camera_num || 0;
         if (h.model) this.camera.model = h.model;
         if (h.resolution) this.camera.resolution = h.resolution;
+        if (h.modes) this.camera.modes = h.modes;
         if (h.controls) this.metered = h.controls;
       } catch (e) {
         this.connected = false;
@@ -202,7 +207,7 @@ function captureApp(cfg) {
         try { await fetch('/api/preview-default', { method: 'POST' }); } catch (e) { /* best effort */ }
         // The reload reset the sensor flip; re-enforce the stored choice.
         if (this.hflip || this.vflip) await this.applyTransform();
-        this.loadControls();
+        await this.loadControls();
         this.pollHistogram();
       }
     },
@@ -219,6 +224,46 @@ function captureApp(cfg) {
       } catch (e) { this.error = 'Failed to set flip'; }
     },
 
+    async switchCamera(num) {
+      this.busy = true; this.error = '';
+      try {
+        const r = await fetch('/api/camera', {
+          method: 'POST', headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ camera_num: Number(num) }),
+        });
+        const h = await r.json();
+        if (!h.camera) { this.error = h.error || 'Failed to switch camera'; return; }
+        this.connected = true;
+        this.cameraNum = h.camera_num || 0;
+        this.camera.model = h.model || '';
+        this.camera.resolution = h.resolution;
+        if (h.modes) this.camera.modes = h.modes;
+        if (h.controls) this.metered = h.controls;
+        this.previewTick = Date.now();  // force the MJPEG <img> to reopen on the new camera
+        // Re-assert the stored flip choice on the new camera.
+        if (this.hflip || this.vflip) await this.applyTransform();
+        await this.loadControls();
+      } catch (e) { this.error = 'Failed to switch camera'; }
+      finally { this.busy = false; }
+    },
+
+    async switchMode(width, height) {
+      this.busy = true; this.error = '';
+      try {
+        const r = await fetch('/api/mode', {
+          method: 'POST', headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ width: Number(width), height: Number(height) }),
+        });
+        const h = await r.json();
+        if (!h.resolution) { this.error = h.error || 'Failed to set mode'; return; }
+        this.camera.resolution = h.resolution;
+        if (h.modes) this.camera.modes = h.modes;
+        this.previewTick = Date.now();  // force the MJPEG <img> to reopen on the new mode
+        await this.loadControls();  // controls may change with mode (frame rate limits etc.)
+      } catch (e) { this.error = 'Failed to switch sensor mode'; }
+      finally { this.busy = false; }
+    },
+
     async loadLightbox() {
       try {
         const r = await fetch('/api/lightbox');
@@ -765,7 +810,7 @@ function resultsApp(cfg) {
     camera: {},           // preview page: {model, resolution} for the live sensor-info box
     metered: { exposure: 0, gain: 0, colour_temp: 0, lux: 0 },  // live metered values
     controls: { auto_exposure: true, exposure: 0, gain: 1, ev: 0 },  // exposure panel state
-    fpsTarget: 30,  // framerate target; 0 = unconstrained (variable frame duration)
+    fpsTarget: 0,  // framerate target; 0 = unconstrained — set by loadControls or user
     lightbox: { present: false, channel: null, intensity: 0, illuminants: {} },  // optional lightbox device
     colour: null,         // current live ΔE reading (for whichever tuning is loaded)
     liveColour: true,     // semi-live colour measurement while previewing
diff --git a/apps/ctt-server/ctt_server/templates/capture.html b/apps/ctt-server/ctt_server/templates/capture.html
index b88f17c..f557180 100644
--- a/apps/ctt-server/ctt_server/templates/capture.html
+++ b/apps/ctt-server/ctt_server/templates/capture.html
@@ -37,9 +37,29 @@
         </div>
       </div>
       <div class="caminfo" x-show="connected" x-cloak>
-        <div class="caminfo-row" style="grid-template-columns: repeat(5, 1fr)">
+        <div class="caminfo-row" style="grid-template-columns: repeat(6, 1fr)">
+          <div>
+            <span class="k">Camera</span>
+            <select class="mode-sel" x-show="cameras.length > 1" @change="switchCamera($event.target.value)">
+              <template x-for="c in cameras" :key="c.num">
+                <option :value="c.num" :selected="c.num === cameraNum"
+                        x-text="c.num + ' · ' + c.model"></option>
+              </template>
+            </select>
+            <span class="v" x-show="!(cameras.length > 1)" x-text="camera.model || '—'"></span>
+          </div>
           <div><span class="k">Sensor</span><span class="v" x-text="camera.model || '—'"></span></div>
-          <div><span class="k">Resolution</span><span class="v" x-text="camera.resolution ? camera.resolution[0] + ' × ' + camera.resolution[1] : '—'"></span></div>
+          <div style="grid-column: span 2">
+            <span class="k">Resolution</span>
+            <select class="mode-sel" x-show="camera.modes.length > 1" @change="switchMode($event.target.value.split('x')[0], $event.target.value.split('x')[1])">
+              <template x-for="m in camera.modes" :key="m.size[0] + 'x' + m.size[1]">
+                <option :value="m.size[0] + 'x' + m.size[1]"
+                        :selected="camera.resolution && m.size[0] === camera.resolution[0] && m.size[1] === camera.resolution[1]"
+                        x-text="m.size[0] + ' × ' + m.size[1] + ' · ' + m.bit_depth + '‑bit · ' + m.fps.toFixed(0) + ' fps'"></option>
+              </template>
+            </select>
+            <span class="v" x-show="!(camera.modes.length > 1)" x-text="camera.resolution ? camera.resolution[0] + ' × ' + camera.resolution[1] : '—'"></span>
+          </div>
           <div>
             <span class="k">Flips</span>
             <div class="seg compact" style="align-self:flex-start">