Hand camera HK 101B addon

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Hand camera HK 101B
Started in 11 January 2023
Contributor(s) Johan G
Status mature
Website https://gitlab.com/JohanG/hk-101b

The Hand camera HK 101B addon adds:

  • An additional key binding, Shift+F3, that will take a screenshot with the below settings.
  • Optionally a shutter sound.
  • Optionally changing field of view to the 35 mm equivalent of 85 mm or 100 mm when taking the screenshot.
  • Maybe possibly eventually optionally a 3D model of a camera.
Note  For technical reasons, when changing field of view is enabled, the screen will flicker as the field of view is changed for a few frames when the screenshot is taken.
The settings dialog.

Historical background

The HK 101B camera was used to document encountered aircraft when doing visual identification (VID) during interceptions, but also for many of the great photos taken by Viggen pilots over the years.

The camera is modeled after the camera used by many Saab 37 Viggen pilots, Handkamera HK 101B (in English literally "hand camera" HK 101B), a modified Contax 137MA with viewfinder and some controls removed, locked, or painted over. The lenses used seem to mostly have been the Carl Zeiss Sonnar T* f/2.8 85 mm and the Carl Zeiss Planar T* f/2 100 mm, with the 85 mm seeming to be more common.

Challenges when using

  • Like in real life there is no view finder, which makes placing the shots a bit more difficult (though unlike real life the camera is always pointing in the same direction as your view).
  • You often end up with shots where the subject is out of frame, in particular when aiming for a composition where the subject is not in the center of the frame.

Tips and tricks

Not missing your shots

  • It is easier to get the subject in frame when you have them in center.
  • Zoom in when you have longer focal lengths, in particular if you have altered it in the property tree (see Tips and tricks below).
  • Practice makes perfect. :-P

Choosing other lenses than 85 and 100 mm

While only 85 and 100 mm lenses are selectable from the settings dialog you can use the property browser and set another value in /addons/by-id/org.flightgear.addons.hk-101b/settings/lens-focal-length-mm.

21, 24 and 36 mm are popular lens choices for interiors, while 200 and 400 mm are popular among plane spotters.

Keep in mind that the focal length will stay if you close FlightGear with the closing dialog from within FlightGear.

Technical details


  • Settings are saved between the sessions, provided you close FlightGear with the closing dialog from within FlightGear.
  • While you can only choose between 85 and 100 mm in the dialog you can change the focal length in the property tree (see Tips and tricks above).

Log file output

The add-on will mention in the fgfs.log file:

  • When a screenshot is taken with the add-on.
  • When all film is exposed (if you have not enabled automatic reloading).
  • When the film is reloaded.
  • When the film is automatically reloaded.
  • When the focal length is changed.

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