ImageReasonLighting, Flash, and Studio
How large does my light source appear to the subject?
Enter your modifier's effective width and height and its distance from the subject to see its apparent angular size, a geometry proxy for softness, not a guarantee.
Answer
Visualize
Calculate to see the angular cone diagram.
Compare
| Scenario | Angular width |
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Plan
Calculate a result to generate a copyable plan.
Apparent size, not just source size
Light-source size is most useful as an apparent-size decision from the subject's point of view. A larger source or a closer source occupies more angle around the subject. That often changes shadow transitions, but it does not determine them alone. Distance also changes falloff and exposure, while the modifier, subject shape, room, and surface all remain part of the result.
A 1.2m-wide source at 1.5m spans about 43.6 degrees horizontally. Double its distance and its apparent area proxy falls to one quarter. Moving it closer may create a broader apparent source while increasing falloff between subject and background. Use the visual geometry to choose what to test, then inspect the actual shadows rather than treating the angle as a softness score.
This result models the values you entered. It cannot see the scene, verify focus or movement, predict camera-specific processing, or guarantee the final photograph. Use it as a stated starting point, then check the important subject area in a test frame or proof.
Make one controlled test with the important variable held constant. Inspect the subject detail, motion, highlights, and intended output, then adjust the setting that protects the priority you named.
FAQ
- Does a bigger softbox always make softer light?
- It can increase apparent size, but distance, shape, diffusion, subject geometry, and environment affect the result. This tool plans geometry, not a guarantee.
- Why no universal best setting?
- There is no universal best setting because the relevant tradeoff changes with the subject, light, movement, output, and the part of the image that matters. This tool makes the stated tradeoff visible rather than hiding it behind a generic recommendation.