Mamiya RB67 Long Exposure System

After doing some research on taking exposures longer than 1 second with the Mamiya RB67, I was presented with two choices. The first purchasing the dual threaded cable release on Ebay for ~80$ USD (at the time of writing this) or manually moving the timer ring on the lens from “T” to “1” to close the shutter. While I was successful in employing the second strategy, the process poses a risk to successful long exposures as it requires manipulating the lens directly which could cause vibrations ruining your shot. Not to mention using a paperclip to manually activate shutter mode means one more thing you need to keep track. Having the clip/paperclip attached to the lens means you don’t have to keep it in hand, which is nice.

The system I created is my attempt to streamline and minimize those risks. If you have a cable release, the clip which goes over the “mirror up” nob isn’t necessary, you can trigger the shutter/mirror up with that and simply use the ring to move the lens from “T” to “1”. As the video shows, you can set the timing ring to “T” then nudge it over the first “bump” without triggering the “close shutter” if you’re careful. Afterwards, when you tug on the hair elastic, you won’t have pull as hard to get the shutter to close. The hair elastic, or whatever you might have available, should also help minimize vibrations. I tried to keep this as simple as possible, and the required parts reflects this. Feel free to switch out parts for what you have on hand, the concept is pretty simple and I’m sure there are numerous part combinations that could be used to complete this task.


  • Paperclip
  • M2 screw/washer/nut
  • Elastic
  • 3D Printed Components
🔗 STL Files ( Link)