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SPECTRA CINE PRO IV and IV-A

Overview:

The Spectra Professional IV-A (see picture of meter and case - file size: 20k.) is an Advanced Digital Exposure Meter (ADEM™). Compact and easy to use, it is the most comprehensive and reliable exposure meter for cinematographers and professional still photographers.

While the Spectra Candella II is calibrated to measure the narrower photopic response curve of the human eye, the Spectra Pro IV-A and Spectra Classic meters are calibrated to measure the spectral response of photographic film. Therefore, while the Spectra Candella II is most useful for industrial/scientific research applications, the Spectra Pro IV-A is most useful for photographic/video applications.

The Spectra Professional IV-A measures incident and reflected light directly in -stops, footcandles or lux and instantly calculates the f/stop difference, contrast ratio and average of your particular lighting situation. The multiple channel memory enables you to recall the stored measurement, current measurement, f/stop difference, contrast ratio and average. The meter covers a sensitivity range of almost one-million to one.

This makes the hand-held incident meter a kind of insurance policy that eliminates second-guessing and gambling with exposure control, especially under the more difficult and extraordinary light conditions that are apt to confront the serious photographer.

The Spectra Professional IV-A has a Digital f-stop measuring range that extends from f/0.24 to f/128 in 1/10-stop increments and the Analog Bargraph range from f/0.7 to f/45 in 1/3-stop increments. Both are displayed simultaneously on a backlit liquid crystal display, along with film-speed, frames per second for cine use or exposure time for still photography.

The digital Spectra professional IV meter was introduced in May 1992 at the American Society Of Cinematographers Club House. The Company believes this is the only digital meter designed to measure Foot-candles, Lux and F/stops - the key unit of measurement used in Cinematography and Television applications.

On February 26, 1993, the company received the "AWARD OF OUTSTANDING ACHIEVEMENT IN ENGINEERING DEVELOPMENT" from the Academy of American Society of Lighting Designers for the Spectra Professional IV meter Technology.

Note: The main difference between the Spectra Pro IV and Pro IV-A meters is the Pro IV-A can automatically calculate contrast ratios as well as average f-stops, lux and footcandles.


Features:

The Pro IV is "must" for movie makers - everyone from students learning about the making of motion picture to the working cinematographer, cameraman or lighting director.

Electroluminescent Backlit Display: Bright green E-L Lamp for reading displayed measurements at very low light levels.

Contrast Ratios and f/stop Difference: The ratio of two illuminance readings from 1:1 to 999:1 can be instantly calculated and displayed - thereby simplifying the setup of any desired lighting situation. In f/stop mode, the f/stop difference is displayed digitally and the two memorized readings (M1, M2) are shown on the bargraph.

Average: Average of the stored measurement and the current measurement can be easily achieved by pressing the READ/ON button. In the f/stop mode, average f/stop is displayed both digitally and as a flashing arrow on the bar graph. In Illuminance mode, the average footcandles are displayed.

Instant Recall of all Measurement and Calculations: By pressing the Recall (RCL) button, the first stored reading (M1), second or current reading (M2), f/stop difference, contrast ratio or average can be recalled.

Immediate Update of all f/stop Calculations: If the film speed (ISO) or the fps/time settings are changed, the f/stops are immediately recalculated and displayed in the Normal, f/stop difference and average modes.

Filter Compensation: The film speed range extends from ISO 3 to 8000 in 1/3-stop increments, enabling you to bias the meter's readings to compensate for filter factors.

Motion Picture Camera Shutter Speed: The Frames Per Second (FPS) range extends from 2 to 360 FPS including 24 for CINE, 25 for PAL TV standard and 30 for NTSC standard.

Camera Shutter Angle: A complete list of shutter angles and the equivalent compensation table is conveniently provided in the instructional material.

Accuracy: The Spectra Professional IV-A is the most accurate meter ever designed and manufactured for cinematographers and still photographers.

Memory Erasure: You can erase the memory (M1 and M2) by pressing the memory STR and RCL buttons simultaneously.


Ratio Mode - How to measure f/stop difference and contrast ratio:

    1. Press the Mode selection button until RATIO appears in the display window. Take a reading and press the memory store (STR) button. M1 will appear in the display window indicating that one value is stored.

    2. Take a second reading and hold the READ/ON button. The f/stop difference or ratio to the first reading will appear in the digital display (in f/stop mode - two f/stop values will also be indicated on the bar graph scale). M1 and M2 will also appear in the display window - indicating the ratio of the current reading to the stored reading.

    3. Release the READ/ON button. The last reading will appear in the digital display (in f/stop mode - two f/stop values will also be indicated on the bar graph scale). M2 will also appear in the display window indicating the second or current (last) reading.


Average Mode - How to measure average f/stop and footcandles:

    1. Press the Mode selection button until AVG appears in the display window. Take a reading and press the memory store (STR) button. M1 will appear in the display window indicating that one value is stored.

    2. Take a second reading and hold the READ/ON button. The average f/stop or average footcandles will appear in the digital display (in f/stop mode - two f/stop values will also be indicated on the bar graph scale with flashing bar indicating their average). M1 and M2 will also appear in the display window - indicating the average of the two readings.

    3. Release the READ/ON button. The last reading will appear in the digital display (in f/stop mode - two f/stop values will remain displayed on the bar graph scale). M2 will also appear in the display window indicating the second or current (last) reading.


Technical Specifications:

TYPE: The Spectra Professional IV-A Advanced Digital Exposure Meter (ADEM™) for measuring Incident and Reflected Light.

TECHNOLOGY: For highest accuracy and reliability, it utilizes Advanced front end op amp, Custom Sealed Hybrid electronic circuitry, Multiple Range Linear Circuit (MRLC) controlled by Advanced microcomputer and custom liquid crystal display with Backlit Electroluminescent lamp.

LIGHT SENSOR: Silicon Photovaltaic cell, Computer selected glass filters tailored to spectral response of the film. Swivel head assembly turns 270 degrees.

MEASURING CAPABILITY: Direct readout of photographic exposures. Measures contrast ratios and average in f-stop and illuminance modes. Measures illuminance level in footcandles (fc) and lux (lx)

MEASURING RANGE: One million to one (20f/stop) direct reading Multiple Range Linear Circuit. Digital f-stop: f.35 to f125 in 1/10-stop increments. Analog f-stop: f0.7to f45 in 1/3-stop increments.

DISPLAY RANGE: ISO: 3 to 8000 in 1/3-stop increments. FRAMES PER SECOND: 2 to 360 (for motion picture cameras). Exposure time: 1/8000sec to 30 minutes.

RESOLUTION: Digital 0.1-stop. Analog: 0.2-stop

ACCURACY: Digital 0.1 f-stop. Calibration is traceable to National Institute Of Standard Technology (NIST), Washington, DC.

ADDITIONAL FUNCTIONS: Memory Recall switch is to recall stored reading in Memory-2 (M2) and/or the Ratio, Average and f/stop difference of the two readings.

LAMP: Electroluminescent lamp for backlit liquid crystal display.

POWER CONSUMPTION: Operating 5 mA/Reading. Data Retention 5uA.

POWER SOURCE: One 6 volt battery no's: A544, PX28L, PX28.

ESTIMATED BATTERY LIFE: Approximately one year with normal use.

DIMENSIONS: 5-1/2" X 2-1/2" X 2"

WEIGHT: Approximately 6 ounces

WARRANTY: Two year limited warranty

RECOMMENDED RE-CALIBRATION PERIOD: Every two to three years (two years or less for meters stored in high humidity environments)

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE


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