Flex 13

With an impressive 1.3 million pixels of resolution, 120 FPS sample rate, and an immense 56° field of view, the Flex 13 is an achievement in efficient, affordable motion capture. Enjoy the precision and accuracy of a professional capture system at a price tuned for AAA and indie studios alike.

Incredibly high precision in an affordable package

The Flex 13’s 1.3 MP imager offers over 4x the resolution of a Flex 3. When combined with OptiTrack’s proprietary real-time processing algorithms, it can track motions within a tolerance of less than 0.5 mm—ideal for rigorous tracking applications, such as multi-actor capture and complex motion tracking.

Maximize your capture volume

You asked for more capture volume, and we were listening. When deployed with the default 56° lens in a standard 20’ × 20’ arrangement, the camera can attain an active capture area that is among the largest in the industry, which allows for extensive capture volumes even in modest tracking environments.

On-camera image processing

The Flex 13 can send a variety of pre-processed image types to the PC, resulting in more efficient imaging and system scaling. Image processing types include:

  • Object – Performs on-camera detection of marker location, size, and roundness using our most precise grayscale processing methods. Provides excellent precision with the smallest CPU footprint.
  • Precision grayscale – Similar to Object processing, but sends selective grayscale images of markers to the PC for calculation of object data. Provides the most verbose marker information, but requires more CPU resources than Object processing.
  • Segment – Like precision grayscale processing, segment mode divides processing between the camera and CPU, providing streamlined marker information for CPU-efficient marker detection. Provides a balance between precision and processing load.
  • MJPEG-compressed grayscale – Full resolution grayscale frames, compressed on-camera for highly scalable scene video capabilities.
  • Raw grayscale – Full resolution, uncompressed grayscale.
MJPEG compression

Unique to OptiTrack cameras, on-camera MJPEG compression consumes 1/10th the bandwidth of uncompressed video while still enabling real-time grayscale video at full resolution and full frame rate (up to 1280 × 1024 @ 120 FPS). Compact, high-quality grayscale video enables image preview with multiple cameras, simultaneously—an indispensable tool for camera aiming and focusing during rig setup and calibration.

Grayscale video access

Access MJPEG grayscale video at up to 120 FPS and transform any Flex 13 into a high-speed scene camera. Simplify camera aiming and calibration, optimize skeleton configuration, provide live capture feedback, and improve post-capture cleanup with a variety of grayscale video options.

Calibrated scene video

Because Flex 13 cameras can operate in grayscale mode, any of the cameras in your volume can be transformed back into a scene camera after calibration, enabling scene video that has exact position and orientation relative to the tracking volume.

Improved skeleton definition

Once scene cameras are calibrated within the volume, you can visually preview potential flaws for a higher level of accuracy. Simply compare the calibrated scene video with overlaid points to confirm that the skeleton aligns with the actor’s body segments and corresponding markers.

Real-time tracking feedback

Monitor the relationship between the actor and skeleton to confirm accurate tracking or to quickly diagnose unexpected behavior. Grayscale scene video is particularly useful during facial motion capture, offering real-time feedback for performance analysis.

3D overlay

Record MJPEG grayscale footage at up to 120 frames per second—5x faster than normal film playback speed. High-speed recording enables the correlation of scene video and tracking data on a frame-by-frame basis for precise analysis or cleanup in post.

Aim Assist – single user camera setup & aiming

One person can efficiently setup and aim a complete Flex 13 system with OptiTrack’s on-camera Aim Assist. One button press brings the camera view to full screen, sets the image to grayscale, retracts the IR filter and increases the exposure for additional lighting and better image clarity. The image is perfect so that placing reference markers on the capture volume floor is no longer necessary. Aim each camera conveniently and precisely without even needing to touch the software interface. Once a camera has been aimed, move on to the next with a single button push.

Flexible filtering options

Customize your Flex 13’s lens filter for standard IR motion capture or visible-spectrum reference video, for light filtering that is perfectly suited to your capture environment and application. Include the Filter Switcher add-on for quickly swapping between both filtering options.

Interchangeable M12 lenses

The Flex 13 can be optimized for a variety of applications with custom-designed, interchangeable M12 lenses. Choose between 5.5mm and 8mm EFL lenses to adapt your cameras to your ideal capture volume. Both feature a special spring focus assist, very low distortion, and fast F#1.8 apertures for increased tracking distance. Typical applications utilize 5.5mm lenses for standard tracking applications and 8mm lenses when additional range or pixel density is required.

Unobtrusive infrared light

Flex 13 cameras emit 850nm IR light, which is nearly invisible, for inconspicuous illumination that prevents the vision fatigue and unwanted attention to your capture rig caused by cameras that emit visible spectrum light.


OptiSync is OptiTrack’s custom synchronization system, which sends and receives sync signals over USB cable. As a result, cabling is reduced by 50%, which enables faster and simpler setup.

External sync in/out

Integrate Flex 13 cameras into scientific and studio ecosystems with external sync in and out, enabled with the OptiHub 2. Utilize frame triggers or free-run triggering to synchronize frame cycling with external software controls and hardware components like force plates and shutter glasses.

If you require Genlock and SMPTE capabilities, please see the Prime Series camera and eSync 2.
OEM integration

Incorporate Flex 13 cameras into custom vision or tracking applications via the free Camera SDK.

Camera Body
  • Width: 2.12 inches (53.8 mm)
  • Height: 3.19 inches (81 mm)
  • Depth: 1.67 inches (42.4 mm)
  • Weight: 6.6 ounces (187 g)
  • Mounting: 1/4″-20 tripod thread
  • Status Indicators:
    • 2 digit numeric LEDs
    • 1 bicolor status LED
LED Ring
  • 28 LEDs
  • 850 nm IR
  • Adjustable brightness
  • Strobe or Continuous Illumination
  • Removable
Lens & Filter
  • Stock Lens: 5.5 mm F#1.8
    • Horizontal FOV: 56°
    • Vertical FOV: 46°
  • Optional Lens: 8 mm F#1.8
    • Horizontal FOV: 42°
    • Vertical FOV: 34°
  • M12 Lens Mount
  • Adjustable focus w/ spring assist
  • 800 nm IR long pass filter
  • Optional: 800 nm IR long pass filter w/ Filter Switcher
Image Sensor
  • Imager Size : 6.144 mm × 4.9152 mm
  • Pixel Size : 4.8 µm × 4.8 µm
  • Imager Resolution : 1280 × 1024 (1.3 Megapixels)
  • Frame Rate: 30-120 FPS (adjustable)
  • Latency: 8.3 ms
  • Shutter Type: Global
  • Shutter Speed:
    • Default: 500 µs
    • Minimum: 20 µs
    • Maximum: 7.5 ms (at 120 FPS)
Image Processing Types
  • Object
  • Segment
  • Precision Grayscale
  • MJPEG Grayscale
  • Raw Grayscale
Input/Output & Power
  • Data: USB 2.0
  • Camera Sync: USB 2.0 (via OptiSync)
  • Power: USB 2.0 @ 1 A
System Requirements

Recommended system requirements can vary significantly based on camera model and count.

Note: Flex 13 cameras must be connect to the PC via an OptHub 2 in order for the LED Ring to be powered. Connecting the camera directly to the PC will result in the LEDs being disabled.
In the Box
  • 1 Flex 13 camera Part number: FL13
  • 1 Quick Start guide

More Information

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Specifications and other information are subject to change without notice. All brand and product names are trademarks or registered trademarks of their respective holders. The information on this webpage is provided by the respective named manufacturer and is for general information purposes. These data constitute a concrete indication of properties and condition only if they are expressly indicated by EST or have been agreed upon as a condition in writing.

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