[Question] Differences in camera image in Isaac Lab and Isaac Sim for the same settings

[hritik-roy-chowdhury]

I have a certain project where I am creating a camera in Isaac Lab. I have another project where I am creating the same camera in an Isaac Sim Replicator script. The camera settings are identical as shown in the code below:

Isaac Sim:

cam = rep.create.camera(focal_length=1.93, focus_distance=0.8, horizontal_aperture=3.896, clipping_range=(0.1, 1000000))
with cam:
  rep.modify.pose(
      position=(1, 0, 1.85)
  )

Isaac Lab:

camera = TiledCameraCfg(
    prim_path="{ENV_REGEX_NS}/camera",
    data_types=["rgb"],
    spawn=sim_utils.PinholeCameraCfg(
        focal_length=1.93, focus_distance=0.8, horizontal_aperture=3.896,
    ),
    width=1280,
    height=960,
    update_period=1/20,
    offset=CameraCfg.OffsetCfg(
        pos=(1.0, 0.0, 1.85), 
        rot=(-0.24184, 0.66446, 0.66446, -0.24184),
    ),
)

The orientations and positions of the cameras are the same. And, I have created scenes in both the Isaac Sim and Isaac Lab projects which are identical too (apart from the configuration of the robot and the number of objects on the tray of course). The comparison between these can be seen in the photos below.

My question: Why are these two cameras showing different views in terms of zoom, viewport etc? All camera properties seem to be the same, and the image dimensions too.

Note: The vertical apertures are not the same, but I saw and changing them makes no difference to the view.

Isaac Lab:

Isaac Sim: (replicator script)

[RandomOakForest]

Thank you for posting this. How are you setting the render_product call for Isaac Sim. Is it the following?

render_product = rep.create.render_product(camera, (1280, 960))

Could you try the following? this may be all is necessary for Isaac Sim to match the TiledCamera:

import omni.replicator.core as rep

# Camera creation with matching intrinsics and pose
camera = rep.create.camera(
    focal_length=1.93,
    focus_distance=0.8,
    horizontal_aperture=3.896,
    clipping_range=(0.1, 1000000)  # Set to a wide range; adjust if needed
)

# Set camera pose using quaternion rotation (x, y, z, w)
with camera:
    rep.modify.pose(
        position=(1.0, 0.0, 1.85),
        rotation=(-0.24184, 0.66446, 0.66446, -0.24184)  # Quaternion (x, y, z, w)
    )

# Create the render product with desired resolution (width, height)
render_product = rep.create.render_product(camera, (1280, 960))

[hritik-roy-chowdhury]

Hi @RandomOakForest,

Thank you for the suggestion.

Yes, my render_product is created in the exact same way as you show. Also, I actually tried a very similar approach to what you show (in the second code snippet) - the only difference being that for the rotation property, I put (0, -50, 0). From this omniverse replicator core API docs, the rotation field must be in degrees - hinting against using quaternions perhaps? In any case, it didn't fix the problem.

I don't think the rotation is an issue here. It is clear from the two photos I shared that the zoom is different in both cases.

[RandomOakForest]

Thank you for following up. I'm going to move this post to our Discussions section to continue and for others to contribute.