diff --git a/services/camera.mjs b/services/camera.mjs
index 93e48e6..8d334f3 100644
--- a/services/camera.mjs
+++ b/services/camera.mjs
@@ -1,4 +1,3 @@
-
 // Camera service (rpicam-apps wrapper)
 //
 // libcamera lets only ONE process own the camera, so everything here goes through a single
@@ -401,11 +400,21 @@ export class CameraService extends EventEmitter {
     }, this.#cfg.streamIdleStopMs);
   }
 
+  // Resolve exposure and frame timing once so preview and recording don't silently
+  // choose different shutter speeds or incompatible frame rates.
+  #cameraPlan(settings, requestedFps) {
+    const shutterUs = settings.shutterUs > 0 ? settings.shutterUs : 0;
+    const fps = shutterUs > 0
+      ? Math.min(Number(requestedFps), 1_000_000 / shutterUs)
+      : Number(requestedFps);
+
+    return { settings, shutterUs, fps: Math.max(0.001, fps) };
+  }
+
   #streamArgs() {
     const c = this.#cfg;
-    const s = this.#settings;
-    const shutter = s.shutterUs > 0 ? Math.min(s.shutterUs, c.streamMaxShutterUs) : 0;
-    const fps = shutter > 0 ? Math.min(c.fps, 1_000_000 / shutter) : c.fps;
+    const plan = this.#cameraPlan(this.#settings, c.fps);
+    const { settings, shutterUs, fps } = plan;
 
     return {
       fps,
@@ -415,8 +424,8 @@ export class CameraService extends EventEmitter {
         '--height', String(c.height),
         '--framerate', fps.toFixed(3),
         '--codec', 'mjpeg',
-        '-q', String(s.quality),
-        ...this.#controlArgs(s, { shutterUs: shutter }),
+        '-q', String(settings.quality),
+        ...this.#controlArgs(settings, { shutterUs }),
         '-o', '-',
       ],
     };
@@ -424,7 +433,7 @@ export class CameraService extends EventEmitter {
 
   #startStream() {
     const { fps, args } = this.#streamArgs();
-    this.#log.info(`starting live view ${this.#cfg.width}x${this.#cfg.height} @ ${fps.toFixed(1)} fps`);
+    this.#log.info(`starting live view ${this.#cfg.width}x${this.#cfg.height} @ ${fps.toFixed(3)} fps`);
 
     const proc = spawn(this.#cfg.vidBin, args, { stdio: ['ignore', 'pipe', 'pipe'] });
     const stream = { proc, fps, expected: false, startedAt: Date.now(), frames: 0, exited: null };
@@ -584,7 +593,8 @@ export class CameraService extends EventEmitter {
 
   #stillArgs(file, settings, { raw = false } = {}) {
     const c = this.#cfg;
-    const manual = settings.shutterUs > 0 && settings.gain > 0;
+    const { shutterUs } = this.#cameraPlan(settings, 1);
+    const manual = shutterUs > 0 && settings.gain > 0;
 
     return [
       '-n',
@@ -681,7 +691,9 @@ export class CameraService extends EventEmitter {
 
     const w = width || c.videoWidth;
     const h = height || c.videoHeight;
-    const f = fps || c.videoFps;
+    const requestedFps = Number(fps || c.videoFps);
+    const plan = this.#cameraPlan(settings, requestedFps);
+    const f = plan.fps;
     const base = `video_${stamp()}`;
     const rawFile = path.join(this.#dirs.videos, `${base}.h264`);
 
@@ -696,7 +708,7 @@ export class CameraService extends EventEmitter {
         '--framerate', String(f),
         '--codec', 'h264',
         '--inline',
-        ...this.#controlArgs(settings),
+        ...this.#controlArgs(plan.settings, { shutterUs: plan.shutterUs }),
         '-o', rawFile,
       ];
 
@@ -750,7 +762,11 @@ export class CameraService extends EventEmitter {
       proc.once('close', (code, signal) => finish(code, signal));
     });
 
-    this.#log.info(`video recording started (${w}x${h} @ ${f} fps${durationSec ? `, ${durationSec}s` : ''})`);
+    this.#log.info(
+      `video recording started (${w}x${h} @ ${f.toFixed(3)} fps` +
+      `${f < requestedFps ? `, limited from ${requestedFps} fps by ${plan.shutterUs}µs shutter` : ''}` +
+      `${durationSec ? `, ${durationSec}s` : ''})`,
+    );
     return this.#jobSummary();
   }
 
@@ -1077,4 +1093,4 @@ export class CameraService extends EventEmitter {
       dir: `/media/timelapse/${job.id}`,
     };
   }
-}
+}
\ No newline at end of file