Spectra Professional IV-A offers a number of important advantages:
Widest Sensitivity Range Ever!
Measures f/stop from f/0.35 to f/128, photographic illuminance from near total darkness- 0.1 footcandles to full 70,000 fc and 1 to 100,000 lux.
Contrast Ratio Measurements (Ratio mode)
The ratio of two readings from l:l to 999:1 can be instantly calculated and displayed thereby simplifying the set-up of any lighting situation. And, in f/stop mode, the difference in f/stop between a new reading and the last memorized measurement is displayed in precise 1/10 –stop increments up to plus or minus 12
Average to two readings and/or continuous averaging in f/stop and footcandles are made possible.
Spectra Professional IV-A Advanced Digital Exposure Meter (ADEM) for measuring both incident and reflected light. Reflected light acceptance angle is 42 degrees-square.
TECHNOLOGY: For highest accuracy and reliability it utilizes an advanced front end op amp, a custom sealed hybrid electronic circuitry, a multiple range linear circuit controlled by advanced mirco-computer and a custom liquid crystal display with aviation green backlit electro-luminescent lamps.
LIGHT SENSOR: Silicon photovoltaic cell with computer selected glass filters tailored to the spectral response of the film. Swivel head assembly turns 270 degrees.
MEASURING CAPABILITY: Direct readout of photographic exposures. Measure contrast ratios and average in f-stop. And in illuminance mode, measures illuminance level in footcandles (fc) and lux (lx).
MEASURING RANGE: One million to one (20 f/stop) widest sensitivity range available. Digital f/stop: f/0.35 to f/128 in 1/10-stop increments. Analog f/0.7 to f/45 in 1/3-stop increments.
PHOTOGRAPHIC ILLUMINANCE: Footcandles 0.1 to 70,000 and lux 1 to 100,000.
CONTRAST RATIO: Calculates ratio of two readings: key plus fill to fill light alone, from 1:1 to 999:1. F/stop Difference: The difference in f/stop between a new reading and the last stored/memorized measurement is display in precise 1/10-stop increments up to plus or minus 12 f/stop.
AVERAGING: Average of two readings and/or continuous averaging in f/stop and
footcandles or lux.
FILM SPEED: ISO 3 TO ISO 8000 in 1/3-stop increments
FRAMES PER SECOND: 2 TO 360 (for motion picture cameras).
EXPOSURE TIME: 1/8000 sec to 30 minutes.
Digital 0.1-stop; Analog 0.2-stop.
ACCURACY: Digital 0.05 f/stop. Calibration is traceable
to National Institute of Standard Technology (NIST)
Memory Recall switch is a recall stored reading in
memory (M1), second reading in memory (M2) and/or the
ratio average and f/stop difference of the two
INSTANT RECALL OF ALL MEASUREMENTS AND CALCULATIONS:
By pressing the recall (RCL) switch, the first
stored/memorized reading (M1), the second
stored/memorized reading (M2), contrast ratio or
brightness (f/stop) difference, average footcandles/lux
or average f/stop, can be recalled.
IMMEDIATE UPDATE OF ALL EXPOSURE
If the film speed (ISO), frames per second/Cine (FPS)
or exposure time/Still (TIME) settings are changed,
the f/stops are immediately recalculated and displayed
in normal, f/stop difference, or average modes.
MEMORY ERASURE: You
can erase the stored/memorized readings in memory (MI)
and memory (M2) by pressing the store (STR) and recall
(RCL) switch simultaneously.
CAMERA SHUTTER ANGLE:
Complete list of shutter angles and equivalent
compensation table conveniently provided in the
BRIGHT GREEN DISPLAY:
Electro-luminescent lamp for viewing displayed
measurements at very low light levels.
SOURCE & CONSUMPTION:
One 6 volt camera battery; No's A544, A544l, PX28l. 5mA/reading. Data Retention 5μA.
BATTERY LIFE: Approximately one year with normal use.
DIMENSIONS & WEIGHT: 5-1/2”
X 2-1/2” X 2”; Approximately 6 ounces.
IV-A MODEL # 18002-A SUPPLIED WITH:
Photosphere (for ambient light), Photodisc (for key or directional light), Leather carrying case,
Neck-strap, 6-volt battery, Instructional manual and warranty card. Two-year limited warranty included.
Specifications Subject to Change without Notice