diff --git a/nerfstudio/viewer_beta/viewer.py b/nerfstudio/viewer_beta/viewer.py
index e577ca5c37..b01c35f4b5 100644
--- a/nerfstudio/viewer_beta/viewer.py
+++ b/nerfstudio/viewer_beta/viewer.py
@@ -259,15 +259,15 @@ def update_camera_poses(self):
         with torch.no_grad():
             assert isinstance(camera_optimizer, CameraOptimizer)
             c2ws_delta = camera_optimizer(torch.tensor(idxs, device=camera_optimizer.device)).cpu().numpy()
-        for idx in idxs:
+        for i, key in enumerate(idxs):
             # both are numpy arrays
-            c2w_orig = self.original_c2w[idx]
-            c2w_delta = c2ws_delta[idx, ...]
+            c2w_orig = self.original_c2w[key]
+            c2w_delta = c2ws_delta[i, ...]
             c2w = c2w_orig @ np.concatenate((c2w_delta, np.array([[0, 0, 0, 1]])), axis=0)
             R = vtf.SO3.from_matrix(c2w[:3, :3])  # type: ignore
             R = R @ vtf.SO3.from_x_radians(np.pi)
-            self.camera_handles[idx].position = c2w[:3, 3] * VISER_NERFSTUDIO_SCALE_RATIO
-            self.camera_handles[idx].wxyz = R.wxyz
+            self.camera_handles[key].position = c2w[:3, 3] * VISER_NERFSTUDIO_SCALE_RATIO
+            self.camera_handles[key].wxyz = R.wxyz
 
     def _interrupt_render(self, _) -> None:
         """Interrupt current render."""
diff --git a/pyproject.toml b/pyproject.toml
index 4c589f6808..b6d11c60c3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -162,6 +162,7 @@ pythonVersion = "3.8"
 pythonPlatform = "Linux"
 
 [tool.ruff]
+line-length = 120
 select = [
     "E",  # pycodestyle errors.
     "F",  # Pyflakes rules.