Sathvick Views: 11 D03 H02 01 Cinematic Focus and Depth of Field in Unreal Engine 5.6

Focusing: Adjusting the lens so that subjects at specific distances are sharp.
Hyperfocal Distance: The closest distance beyond which everything remains in focus.
- Human eye hyperfocal ≈ 25 cm.
- Smaller focal length = shorter hyperfocal distance (e.g., GoPro).
- Longer focal length = larger hyperfocal distance (e.g., 50mm f/1.2 ≈ 30 meters).

Focus ring (manual adjustment) shifts lens to match object distance.
Pull Focus: Changing focus between subjects (e.g., actor to background) in cinema.
Accommodation: Human eye's focusing behavior when viewing near objects.

Definition: The range (front to back) in which subjects appear acceptably sharp.
Factors Affecting DoF:
- Aperture (f-number):
  - Low f-number (e.g., f/1.2) → shallow DoF, blurry background.
  - High f-number (e.g., f/16) → deep DoF, everything in focus.
- Focal Length:
  - Wide-angle lenses (e.g., 20mm) → greater DoF.
  - Telephoto lenses (e.g., 75mm) → shallow DoF.
- Object Distance: Closer subjects reduce DoF.

Cameras simulated:
- GoPro (6.17mm x 4.63mm) with 4mm focal length & squeeze factor 1.5.
- iPhone (9.8mm x 7.3mm) with adjustable aperture and focus.
- ARRI Alexa (54.12mm x 25.58mm) with 60mm lens.
Enabled Auto Exposure for consistent lighting during aperture changes.
Demonstrated:
- Changing Aperture from f/1.2 to f/16 to vary DoF.
- Changing Focal Length from 16mm to 75mm to demonstrate focus behavior.
- Impact of focus shifts using eyedropper tool.
- How blur varies with focal length and aperture combination.

For sharp background & foreground: Use wide-angle lens + high aperture (f/11 or f/16).
For blurry background (bokeh effect): Use telephoto lens + low aperture (f/1.4 or f/2).
You can animate focus in Unreal to create pull focus shots using sequencer.

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