March 30, 2022
Description
This is an big tube adapter to fit on the front of a nikon camera and to screw a Pentacon 80mm ƒ/2.8 projection lens into. Get beautiful soap bubble bokeh for so much less than a trioplan lens.
This is not a generic pentacon mount to f-mount. This is one specific slide projector lens (pentacon 2.8/80 AV) to Nikon f-mount. There may even be different sizes of this one lens. This one had a barrel diameter a little over 51mm (over 2 inches). Might be called a Pentagon XL.
This adapter comes in two parts that should snap together but you can glue together if you choose to. Has an internal tooth that fits into a groove on the projector completing a focusing helicoid. The lens can then be twisted to focus. The adapter also has a lip you could glue some scrap felt into to give some dampening.
If you need infinity focus you might have to cut off the last 5mm of the lens's plastic housing so the lens can move in closer to the camera. Be sure to protect the back element of the lens from being scratched while your are cutting. A scratched back element really wrecks the image.
Edit: Added a new Nikon F-mount stub as the last one had some faces missing. Printed fine but was not manifold. The new F-mount adapter is thicker and has much tighter tolerances. Any excess material must be removed for it to fit in the camera.
Printer:
Anycubic i3 mega
Resolution:
.2mm & 30mm/s worked for me.
Infill:
No
Notes:
Has small overhangs that should be OK without support - they don't even need to be perfect.
If you can get away with it this is meant to be printed without rafts or brims. Makes clean up easier. If you have to sand or cut off excess material think of a way to wash and clean the print before you put it on your camera. I don't want you to get plastic debris in your camera.Learning sketchup. Worked with beautiful 60 sided polygons.
For more mechanical adapters and to tweek designs better I think I will have to switch over to FreeCAD.
I think a lot of other projector lenses could be adapted the same way. Measure the diameter and build a tube for them. My f-mount stub is Ø42mm where it goes into this tube so it could easily be re-used to snap into other tube like adapters.
License:
Creative Commons — Attribution
KaJashey
