Lighting and Light Theory
What this domain tests
Lighting and Light Theory tests how you shape, measure, and balance light: source size and distance, direction, color, contrast, and the relationship between ambient and flash. It rewards prediction, not kit memorization.
Core rules
- Hard light comes from a small apparent source; soft light comes from a large apparent source relative to the subject. Move a softbox closer to make it softer and to increase falloff.
- The inverse square law applies to point sources: doubling distance reduces intensity to one quarter, or two stops. Large modifiers and nearby walls make falloff less exact.
- Lighting ratios compare key and fill intensity. f/8 key with f/5.6 fill is 2:1 because one stop equals twice the light. f/11 key with f/5.6 fill is 4:1.
- Color temperature is measured in kelvin. Daylight is roughly 5500 K; tungsten is roughly 3200 K. Mixed light creates casts that white balance cannot fully neutralize across the frame.
- Incident metering reads light falling on the subject; reflected metering reads light bouncing back and can be fooled by bright or dark subjects.
- Flash exposure is governed by aperture, flash power, and distance; ambient exposure is governed by shutter, aperture, and ISO. Sync speed limits when the whole frame is open to flash.
Worked example
A bare flash at 2 m gives f/11. Move it to 4 m. Distance doubles, so intensity falls to one quarter: two stops. f/11 to f/8 is one stop, f/8 to f/5.6 is two. The new aperture is about f/5.6, assuming the same power and no bounce. If you needed f/11 at 4 m, you would need four times the flash power, not twice.
Traps that cost marks
- Confusing soft light with low contrast; a large source can still be directional.
- Treating lighting ratios as linear brightness instead of stops.
- Forgetting that shutter speed does not control flash brightness within sync speed.
- Ignoring color temperature when mixing flash, tungsten, and daylight.
- Applying inverse square precisely to a huge modifier at close range.