New Digital Servo 
The 4ML’s lean digital servo shown here eliminates all servo analog components with a dedicated, on-board 16-BIT microcontroller and proprietary servo algorithm. A programmable logic array and a high-accuracy, temperature-compensated crystal control all camera functions—including frame rate, protection circuits and timing light generator. The digital servo combines leading-edge surface mount technology with custom flex circuitry for reliability even in the most severe environments—making the 4ML still the most accurate, high-speed 35mm camera in the world.

Boresight Alignment & Focus
Quick-locking in place of a magazine, the 4ML’s boresight tool positions its ground glass at the actual film plane to assure critical alignment and focus. This design is far superior to mirrors and retractable optics that often produce unexpected results on the film. The boresight tool pictured provides 10X magnification and is supplied with two adapters:  one right angle, and one straight allowing side, top and back viewing for maximum flexibility. Spring-loaded ground glass assembly assures perfect focus at the film plane. Details of video boresights and reflex viewers are available upon request. 

 Streamlined Film Transport
A truly clean film transport assures smooth, trouble-free operation with an absolute film registration accuracy of ±.0002 inch. Permanently lubricated stainless steel bearings are used throughout plus two register pins of hardened steel and two pulldown pins of high-strength 7075-T6 aluminum, hard chrome plated and precision ground for maximum strength and durability.

 4ML Standard Equipment 
Includes a 28V DC motor (115V AC 50/400 Hz motor available as an option), and a variable shutter along with top, bottom and side mounting provisions. Other features include continuously variable speeds from 10 to 200 fps, a runout switch and 115V AC thermostatically controlled heater for operation to –65°F. (28 volt heater optional) The camera is equipped with a Photo-Sonics interrupted-thread lens mount and dust cover, camera cover, dual LED timing lights, manual advance knob and a convenient press-to-test switch for slow speed film advance.

Modular Electronics
Solid-state electronics, together with pulse width modulated speed control, create a system inherently less sensitive to voltage and temperature variations, providing far greater accuracy and stability than comparable analog systems. Plus, a unique protection circuit prevents damage to the electronics in the event of a film jam.

Camera Heater
Positioned between the camera and magazine, a thermostatically controlled 115V AC heater enables the camera to operate at temperatures as low as –65°F. (28 volt heater is optional)  Unique control circuitry turns the heater off at camera start to reduce power consumption, and during magazine exchange to prevent damage to the heater element.

Remote Slow Speed Film Advance
This advancement removes any loop set in the film due to continued low temperature soaking prior to camera start.

Automatic Exposure Control (optional)
The 4ML is pre-wired to accept the field-proven Apex-B bolt-on automatic exposure control system. The Apex-B mounts quickly and easily to the front plate of the 4ML. The 4ML electronics can be programmed to automatically shut off power to the Apex-B at camera start to ensure exposure is not affected by event illumination.

Variable Shutter (optional)
Adjustments to the 4ML’s shutter are made quickly and easily without the use of tools. The variable shutter adjusts between 9 and 144° simply by holding the rear motor knob while pulling and turning the front shutter knob. Adjustment takes only seconds.

Remote Status Indicators
Camera-ready and phase-lock status can be checked using the 4ML’s remote status indicators. This advancement simplifies pre-flight checking of multiple cameras and reduces the risk of data loss and costly retesting.

Film Data Recording System (optional)
The 4ML can be equipped with a Film Data Recording System (FDRS) which prints IRIG-B time, event and status information on each frame of film. The FDRS consists of a sub-miniature, 20-digit, 7‑segment LED matrix, installed directly in the camera aperture and an electronic driver mounted on the side of the 4ML camera. This configuration is impervious to humidity, vibration, and other harsh environments that can cause fogging and misalignment in systems using mirrors and relay optics.

Built-In Timing Light Generator 
This optional feature is used to drive one of the edge-of-film LED timing lights and will print serial IRIG‑B or automatically select 10, 100, or 1,000 pulses per second.  

Plug-In AC and DC Amplifiers
Plug-in AC and DC servo amplifiers are small enough to fit in the palm of your hand yet install easily in seconds. The amplifier features unique reverse polarity protection. The AC amplifier provides 28-volt power to Film Data Recording System and Apex-B automatic exposure control, eliminating the need for a separate DC power source for these accessories.

Variable shutter can be externally adjusted quickly and easily with no tools; no re-timing of camera required.

Interchangeable motor, power amplifier and phase lock electronics

Out-of-film indicator. Contact closure to 28V DC return when magazine is out of film.

Plug-in AC or DC amplifier. DC power amplifier has unique reverse polarity protection.

Ready and Phase lock indictor and TTL level output allows remote monitoring of the camera status.

Camera can be converted from AC to DC by changing the motor and power amplifier.

Digital Phase Lock Speed Control requires no calibration.

Phase Lock to IRIG-B or an external reference frequency for simplified data reduction.

LED timing light may be easily replaced from outside the camera, without disturbing the film load.

Magazines can be quickly interchanged  allowing the camera to remain mechanically, optically and 
    electrically installed on tracking mount or environmental housing.

If usage dictates different film capacities, different film magazines are available rather than purchasing an 
    entire new camera. 200, 400 or 1000 foot magazines interchange in less than five seconds with no 
    adjustment to camera or magazine.

Intermittent pin-registration for precise registration and accurate data collection.

Magazine can only be properly threaded one way, timing mark offset is always 7 ½ frames.

Magazines are near-automatic threading with no climbing loop

The 35mm-4ML camera is designed and manufactured to obtain high-speed, high-quality motion pictures at frame rates from 10 to 200 frames per second under adverse environmental conditions.

The following tests have been performed on the 1PL camera which is electrically identical and mechanically similar to the 4ML:

Random Vibration	X and Y axis 19.27 G’s (rms) 20-2500 Hz Z axis 27.5 G’s (rms) 10-2000 Hz
Temperature	-65°F to +160°F
Altitude	70,000 feet
Humidity	MIL-STD-810B Method 507 Procedure I (5 cycles)
Acoustic Noise	160 decibels
EMI	RE02, MIL-STD-461C, Part 3, Class A2B, MIL-STD-461A Notice 3 and MIL-STD-462