Auto-Focus Tables

  An Auto-Focus Control System consists of an Auto-Focus table for the selected camera and lens and a micro-processor based controller.  The system assures proper focus with long focal length lenses.  Accepting precise slant range data via parallel, serial or  Ethernet interface from a ranging source, the system calculates and precisely positions the camera mounting table to assure optimum image focus.

The Auto-Focus Systems, the AF-1 and AF-2, provide automatic focusing for a variety of long focal length lenses for film, digital and video cameras used on Photo-Sonics tracking mounts and other compatible platforms.  The Model AF-1 is designed for the Cine Sextant and KTM platforms. The AF-2 is used primarily with the Compact Tracking Mount.

  Maintains Precise Camera Focus
● Compatible with all Fixed Focal Length Lens and Camera Combinations.
● No Supplemental Optics in Film Path to Cause Loss of Resolution or Contrast.
● No Rotating Optics to Displace Image.
● Parallel, Serial and Ethernet Interface.
● For Use with Film, Video and Digital Cameras.
● New processor can be retrofit to existing Photo-Sonics compatible Auto-Focus tables.

AF-1 Auto-Focus Table

AF-2 Auto-Focus Table  
  AF-1 Auto-Focus Table AF-2 Auto-Focus Table  
  Auto-Focus Table
The Auto-Focus Table accepts a ±10VDC drive signal from the Processor/Controller and moves the mounting table along the optical axis of the camera/lens system.  The camera mounted on this table is moved with respect to the principal focus of the lens system changing the distance to the film plane, varying the system focus.  Output from a linear encoder attached to the drive system provides positional feedback to the Processor/Controller.
AF-2 with 35mm-4EL Camera  
                  AF-2 with 35mm-4EL Camera  
Auto-Focus Processor
Photo-Sonics has developed a new Auto-Focus Processor based on a Intel processor mounted on a PC-104 board set. This processor is  compatible with both the AF-1 and AF-2 Auto-Focus Tables. The processor is located inside the AF-1 table. A separate enclosure is provided for the AF-2 tables. The New Auto-Focus Processor computes positional information from range and focal length inputs and generates motor drive signals to the Auto-Focus table. The standard system will accept range data via Parallel, Serial, or Ethernet interface. The Serial or Ethernet interface is also used to custom configure the processor and initiate special test and calibration functions. To help reduce system tracking error, the controller includes a range data "look ahead" feature.  In the temporary absence of range data, the system will calculate a projected new target position based on the previous samples.  This function can be enabled and disabled by the operator.

Test Mode
Two test modes are built into the Processor/Controller.  One tests system stability by automatically generating a series of input commands to fully exercise the table.   A second test mode requires the input of manual range values to drive the table to the calculated position for the focal length programmed.  These test modes may also be used to confirm system calibration. 

Calibration  requires auto-collimation to find the infinity setting.  The lens focal length is manually input. Additional methods of calibration are optional.

Custom options include programming the processor to accept special serial and Ethernet data and to provide coordinate translation to allow the system to maintain focus from data provided by a Nearby Device or Range Control Center that has a reference point which is off-set from the position of the optical tracking system on which the focusing system is mounted. 

Existing compatible Photo-Sonics Focusing Tables can be retrofit with the new Auto-Focus Processor. Contact the Photo-Sonics sales department for further details.


New Back Panel for the AF-1 autofocus table.

New AF-1 Back Panel

             System Specifications



Range (with 200" lens) Minimum - 1200 feet
Maximum - 213,000 feet (infinity)
Minimum - 1700 feet
Maximum - 213,000 feet (infinity)
Load Capacity 200 lbs. 150 lbs.
Accuracy ±0.0005 inch of theoretical curve for any lens ±0.0005 inch of theoretical curve for any lens
Velocity Maximum 3 inches/second Maximum .5 inches/second
Maximum Travel 3" 2"
Acceleration Maximum 1.5 inches/sec/sec Maximum 7 inches/sec/sec
Input ±10VDC drive ±10VDC drive
Output Table position from optical incremental encoder .0005 inch/pulse with reference marker. Table position from optical incremental encoder .0005 inch/pulse with reference marker.
Power 115VAC, 2A max. 28VAC, 2A max.

Photo-Sonics, Inc.
    818-842-2141     (ph - switchboard paging)
    818-842-2610     (fax)
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