11/8/2024 update: A friend of mine asked the same adapter to use on Samyang/Rokinon 135/F2 lens. Using the same process, created another model for Rokinon's 4 screw hole pattern. Remove any 3 out of 4 screws and use three M1.7 - 10mm screws to connect the same way. Screw hole patterns are the same over models on the same brand. So it works for Rokinon 14mm/F2.8 as well.
I have old Nikkor 105/F1.8 lens and I wanted to use this for Astrophotography but my club members told me ZWO's F-mount ASI camera adapter or filter slider are not good as there are too much slack and causes tilt.
Since there is mechanical DoF lever and aperture ring control, you can't replace back flange to threads adapter. So, I studied and measured F-mount back flange dimensions to create this model as 'add-on' adapter.
Here is the step showed in pictures.
Nikon F-mount requires 46.5mm flange to focal plane distance to focus infinity.
This adapter will provide 8mm and you'll need to make rest of optical path as 38.5mm.
I designed this 8mm thickness to make 21mm ZWO filter slider and ASI Pro camera's 17.5mm BF in mind, so it would work the best. But any filter slider like Starizona's one with 4.5mm ring would work too as shown in the last picture, as long as the back focus distance meets 38.5mm.
I have CNC, so made this out of Aluminum you can see one of the picture but this printed adapter will work as well. I carefully adjusted thread tolerance to have good fit on ZWO's 16.5mm M48 ring.
Note that depending on your layer seam location, thread could feel tight at first but once it is threaded, it will slide in. Be careful not to have cross-thread when you thread in. 3D printed thread won't survive cross-thread.
The inner thread is M42/0.75 female but it's not designed to connect something but designed to suppress internal reflection.
| fmount_m48_nikkor.stl | 3.9MB | |
| fmount_m48_rokinon.stl | 3.8MB |
