10 D02 H01 P02 Focal Length and Field of View Settings in Unreal Engine 5.6

Session 9 – Summary: Understanding Focal Length & Lens Behavior in Unreal Engine

🔍 Camera & Lens Fundamentals

• Focal Length: Distance between the lens center and image plane; affects field of view (FoV).

  • Short focal length → wide-angle view (e.g., 20mm).

  • Long focal length → narrow FoV, zoomed-in (e.g., 200mm, telephoto).

• Lens Power: Measured in diopters; 1 diopter = standard eye power.

• Normal Lens: Focal length equal to the sensor's diagonal size.

• Field of View: Wider FoV at shorter focal lengths; directly influenced by sensor size.

📏 Sensor Size Examples

• iPhone: 9.8mm x 7.3mm → ~13mm is normal lens.

• Blackmagic: 25.34mm x 14.25mm → ~30mm is normal lens.

• ARRI Alexa: 54.12mm x 25.58mm → ~60mm is normal lens.

📸 Practical Setup in Unreal Engine 5.6

• Download and extract camera_settings.zip and metahumans.zip.

• Import Metahuman assets into the Content/INT_VC/ directory.

• Add Cine Camera Actor in the level.

• Use real camera sensor specs (from VFXcamdb.com) to simulate specific camera types.

• Adjust focal length per camera type (ARRI, Blackmagic, iPhone).

• Focus Settings: Use eyedropper tool or manually adjust to ensure sharp focus.

• Use Omni Calculator to compute sensor diagonal = normal focal length.

• Use multiple viewports to compare cameras side by side in Unreal.

🔧 Unreal Engine Camera Workflow

• Game view toggle: G key hides UI clutter.

• Set Film Back Width & Height for accurate simulation.

• Adjust Lens Settings → Focal Length to explore wide/normal/tele views.

• Use Viewport Splits to compare ARRI, Blackmagic, and iPhone setups.

🧪 Observations

• Same focal length yields different results across different sensor sizes.

• Normal field of view ≈ 45–50°.

• Focal length affects perspective, depth compression, and background scale.