Specifications

MODEL 370 REV: D Page 22 of 26
B = brightness of object measured in candelas/sq.ft.
I = illumination on camera image plane in footcandles.
= B/(4(f#)
2
)
Illumination at object plane if camera is removed and film placed directly at
location of camera image plane
= B (footcandles) = 10.76 B (lux)
6.8 Conversion Factors
LUMINANCE (PHOTOMETRIC BRIGHTNESS) CONVERSION FACTORS
1 NIT = 1 CANDELA/SQUARED METER
1 STILB = 1 CANDELA/SQUARED CENTIMETER
1 APOSTILB (INTERNATIONAL) = 0.1 MILLILAMBERT = 1 BLONDEL
1 APOSTILB (GERMAN HEFNER) = 0.09 MILLILAMBERT
1 LAMBERT = 1000 MILLILAMBERTS
Multiply number of
To Obtain By foot- Candela milli- candela/ candela/
Number of lambert sq. m. lambert sq.in. sq.ft. stilb
footlambert 1 0.2919 0.929 452 3.143 2,919
candela/sq.m. 3.426 1 3.183 1,550 10.76 10,000
millilambert 1.076 0.3142 1 487 3.382 3,142
candela/sq.in. 0.00221 0.000645 0.000205 1 0.00694 6.45
candela/sq.ft. 0.3183 0.0929 0.2957 144 1 929
stilb 0.00034 0.0001 0.00032 0.155 0.00108 1
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com