Color Temperature & White Balance vs. F-Stop Scale
Comparing 2 standards across 13 specifications. 13 key differences identified.
Color Temperature (measured in Kelvin / K, standardized under CIE illuminant standards) defines the spectral chromaticity of light emitted by an idealized black-body radiator. Governing camera white balance, it ranges from warm Candlelight (1800K) and Tungsten Studio (3200K) through Photographic Daylight (5600K / CIE D55) to Overcast Sky (6500K / CIE D65) and Deep Blue Shade (8000K–10000K).
The F-Stop Scale is a standardized geometric progression of lens focal ratios (N = f / D, where f is focal length and D is entrance pupil diameter) governed by powers of √2 ≈ 1.4142. Advancing one full stop (e.g. from f/2.8 to f/4.0) halves the cross-sectional area of the optical entrance pupil, cutting light transmission precisely in half (-1 EV).
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Tungsten / Halogen Standard
|
3200 K (Standard interior film incandescent / studio tungsten quartz lighting) | — |
|
Commercial Warm White Home Lighting
|
2700 K to 3000 K (Warm ambient household LEDs and Edison bulbs) | — |
|
Direct Sunlight / Flash Standard
|
5500 K to 5600 K (Standard photographic electronic flash and noon direct sunlight) | — |
|
CIE Standard Illuminant D65
|
6504 K (Standard average daylight definition, sRGB / Rec.709 / Display P3 monitor white point) | — |
|
Overcast Sky & Open Shade
|
6500 K to 8000 K (Cool blue-tinted indirect atmospheric skylight) | — |
|
Mired Shift Calculation
|
Mired = 1,000,000 / Kelvin (Used for precise optical color temperature warming/cooling filters) | — |
|
Tint Tint Scale (Green / Magenta)
|
Orthogonal CC tint axis (corrects for fluorescent mercury gas spikes and green LED CRI spikes) | — |
|
Mathematical Definition
|
— | F-Number N = Focal Length (f) / Entrance Pupil Diameter (D) |
|
Geometric Progression Factor
|
— | Powers of √2 (~1.41421356...): √2⁰=1.0, √2¹=1.4, √2²=2.0, √2³=2.8, √2⁴=4.0, √2⁵=5.6, √2⁶=8.0, √2⁷=11.3, √2⁸=16.0, √2⁹=22.6 |
|
Standard Full-Stop Scale
|
— | f/1.0 -> f/1.4 -> f/2.0 -> f/2.8 -> f/4.0 -> f/5.6 -> f/8.0 -> f/11 -> f/16 -> f/22 -> f/32 |
|
Standard 1/3-Stop Increments
|
— | f/1.4, f/1.6, f/1.8, f/2.0, f/2.2, f/2.5, f/2.8, f/3.2, f/3.5, f/4.0, f/4.5, f/5.0, f/5.6, f/6.3, f/7.1, f/8.0, f/9.0, f/10, f/11, f/13, f/14, f/16 |
|
Light Transmission Rule
|
— | Each full f-stop increase cuts light passing through the lens by exactly 50% (1 stop / 1 EV) |
|
Diffraction Limit Physics
|
— | Airy disk diameter = 2.44 × λ × N. At f/16 and f/22 on high-res digital sensors, diffraction visibly softens fine detail |