o Screen Brightness and Uniformity
o Contrast Ratios
o Stray Light And Surround Brightness
o Movie and Slide Projection Systems
o Television Monitors
o Set Lighting
Photometer for measuring illumination intensity and luminance/
brightness measurements with 10 PhotoSpot
TECHNOLOGY: Dual stage front
end op-amplifier, custom sealed hybrid integrated circuitry, multiple
range linear circuit controlled by
microcomputer and custom back-lit liquid crystal display for highest
accuracy and reliability. Ultra-stable silicon detector.
CORRECTED: Cosine correction is accomplished by using a specially
designed white molded plastic diffuser receptor. The diffuser provides
cosine correction to a high degree of refinements; thus the detector
correctly evaluates the light intensity regardless of direction.
As a beam of light is titled so that it strikes a surface at an angle,
the area covered by the beam increases. Since the amount of light in the
beam remains constant, the illumination on the surface decreases. This
decrease is proportional to the cosine of the angle, which the incident
beam makes with a perpendicular to the surface.
The meter reading of a fully cosine-corrected light meter represents the
true illumination of the light receiver regardless of the angle from
which the light approaches. Cosine error is +/- 1%. See Cosine Corrected
curve for candela II photometer.
Computer selected glass filters are designed to match the meter's
detector response to the CIE photopic response
(human eye response), which defines the eye's sensitivity to color. The
combined spectra response is the product of the filter's transmission and
the spectral responsivity of the detector. The photopic response of the photometer matches the CIE
standard observer curve response to within 2.5% of the reading when using
a standard tungsten source at 2856°K.
CAPABILITY: Measures illuminance level in
foot-candles (fc) and lux
(lx); luminance measurement with PhotoSpot in
foot-lamberts (fl) or cd/m2.
Light Sensor: Silicon
Photodiode with V (λ) filter.
LEVELS: 0.1 to 70,000 fc and 1 to 100,000
LEVELS: 0.1 to 70,000 fl or cd/m2 (with 1° PhotoSpot
MEMORY: Can store up to
two readings in meter memory with store/ recall switch.
repeatability: +/- 0.2%
RATIO: Calculates ratio of two readings from l.0:l
to 999:I. in fc or fl.
*AVERAGING: Average of
multiple readings and or continuous averaging in foot-candle or
foot-lamberts modes are made possible.
ACCURACY: +/- 5% of the
full-scale value, when measuring blackbody sources.
CALIBRATION: Calibration is
traceable to the National Institute of Standard Technology (NIST). NIST
traceable calibration certificate included.
lamp for viewing displayed measurements at very low light levels.
RANGE: For maximum accuracy 32° to 130°F or 0° to 55° C.
POWER SOURCE: One 6 volt
battery #A544, PX28L, PX28.
DIMENSIONS: 5 ½" X 2
½" X 2". Weight 6 ounces.
WARRANTY: One year limited
II-a meters are supplied with : Photodisc (cosine
corrected for key or directional light), Leather carrying case,
Neck-strap, 6-volt battery, NIST traceable calibration and Certification,
Instructional manual and Warranty card.
All Spectra Candela II A- SP
meters are supplied with: Candela IIA Illuminance
photometer, Luminance one degree PhotoSpot spotmeter all supplied in attractive, sturdy
foam-lined protective carrying case with space for accessories, Instruction
Manual, NIST traceable calibration and Certification and Battery.
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