2025-05-19

photography

notes

fundamental variables for light in a studio

emission and geometry

  • collimation: degree to which rays travel parallel (focused vs diffuse)
  • angle: incidence angle shapes shadow hardness and direction
  • distance: source–subject gap governs intensity (inverse-square law) and coverage
  • shape: source outline (edgy, round, asymmetric) modifies distribution
  • gradient: transition sharpness (sharp vs soft); e.g. softbox centre-to-edge falloff
  • layering: overlap of separate light zones for depth and separation
  • count: number of discrete sources affecting complexity

intensity and quality

  • intensity: relative brightness controlling highlight prominence
  • bloom: lens/filter/sensor glow from internal scatter
  • scatter: light diffusion by particles or surfaces

spectral

  • color: correlated color temperature and tint balance

focal length

refractive shaping (lens)

  • bends rays by curvature and refractive index
  • converges or diverges parallel rays to focal points
  • reorganises ray density and direction via wavefront shaping

lens structure note

  • longer focal lengths require greater sensor-lens distances
  • this necessitates physically longer lens barrels
  • these enclosures incidentally cause angular filtering, blocking oblique rays
  • the resulting geometric occlusion is not a focal length effect per se, but a structural consequence
  • it reinforces the directional narrowing already inherent in long focal length optics

focus and ray density

out of focus

  • rays from a point fail to converge on sensor plane
  • form blur circles; spatial misplacement causes loss of sharpness

low ray density

  • fewer rays per area reduces local brightness
  • can occur with correct focus under dim or oblique lighting

source size and distance

  • distant extended source subtends a small angle → appears point-like
  • only narrow cone of rays reaches observer → angular collapse
  • no actual rays blocked; spatial detail is angularly compressed

lighting motivation

what makes sunlight or window light appear natural?

  • large relative source size → soft, gradual shadows
  • consistent directionality → typically from one side and above
  • stable, coherent color → except during golden hour or under foliage
  • shaped by environment → indirect bounce from walls, ceilings, and ground
  • visual simplicity → usually a single dominant source, not multiple competing ones

why studio lighting often appears artificial

  • multiple unmotivated sources → cluttered, directionless light
  • unnatural placements → e.g. under-chin kicker lights
  • excessive uniformity → no gradient, falloff, or believable shadow structure
  • mismatched scale or placement → small sources too close, or flat-on frontal lighting that flattens form

reference practice (mips)

  • study others’ photography, cgi art and film stills for lighting ideas

backgrounds

  • lighting background creates gradients and color effects
  • black: intense, mysterious, elegant
  • white: airy, clean, high-key

  • materials: choose seamless surfaces (e.g. carton)

    • use regular-edged tape to avoid uneven shadow lines

lighting principles

  • inverse-square law: intensity ∝ 1 / distance²
  • diffuse light: larger area increases softness; distance still governs falloff