Petri breech lock bayonet adapter DIY

roglebk · Joined: 13 Mar 2018 Posts: 60

This is a cheaper alternative to the 45 USD adapters. Use a M42 adapter, Nex Sony E M4/3 and so on. The ones with 3 hex screws that holds the chrome M42 ring. Remove the ring, bayonet lugs fits inside and lines up with the holes so screws can be used to secure lens to adapter. Register distance is almost the same, M42 45.46 Petri 45.50mm, so infinity focus is possible. It's reversible for both lens and adapter. Will post pics later.

Petri Tele Kinegon 135mm 3.5 seen here:
http://forum.mflenses.com/tele-kinegon-f3-5-135mm-no-23529e-help-with-mount-t79486.html

DConvert · Joined: 12 Jun 2010 Posts: 921 Location: Essex UK

Thanks for the tip
Those 2 part adapters do prove a big advantage Like Dog

kiddo · Joined: 29 Jun 2018 Posts: 1275

Just tried it and it won't be that easy. After removing the 3 screws ,the petri breechlock mount won't fit inside, so I had to remove some of the part of the mount with a Dremel. Once it got Inside, the 3 screws won't lock the lens inside the adapter , but as it got inside pretty tough, I was capable to use it. The infinity will reach on 8 meters in the lens, besides that, the only secure way would be to glue the lens to the adapter. Good sharpness wide open and nice colours,haven't got chance to see the bokeh,Wich was my first interest .....

roglebk · Joined: 13 Mar 2018 Posts: 60

What lens and adapter did you use? It worked fine with a Sankor made Kinegon 135 and M42 adapter, no machining needed and screws lined up. Infinity was a bit off though after testing so had to adjust the focus.

kiddo · Joined: 29 Jun 2018 Posts: 1275

I've used the Petri 55 1.8 breechlock, the mount couldn't get inside the M42 tube,so I've had to remove about 1 mm each side; once inside , the screws would lock the lens,and fitting the lens all the way inside the tube, would reach infinity around 8 meters, but still could try the lens and definitely worth the effort to adapt it. Is a very good and tiny lens. I understand that the breechlovk diameter is the same on sankor lens or whatever, meantime is the same mount. So,probably might be another mount that the Sankor has? Or maybe theM42 tube you've got is a bit larger (could be) with a thiner inner threaded ring

roglebk · Joined: 13 Mar 2018 Posts: 60

Yes, either the Sankor mount is a bit smaller in diameter or the adapter i used is larger. It's a Petri mount for sure.