Astro Camera to Nikon AF-S Glens adapter

[JayPea]

Hi,

I thought some might be interested in a simple DIY adapter to connect to Nikon AF-S G lenses, in my case to an uncooled ZWO camera. As I’m looking at using my Nikon G lenses but the catch is they don’t have the aperture ring to manually open the aperture when not used on a Nikon camera. I’d seen several people use attachments based around the QSI Nikon adapter with the manual aperture control but at $250/£198 it was bit over my budget. I’d done the usual searches but I couldn’t be sure exactly what bits to buy to guarantee I could just screw on a ZWO to a Nikon G lens and it would work, i.e. the correct spacing and would open the aperture.

I already had a cheap (only £5.99 + £1 p&p off Amazon) extension tube set made by Fotga. This was the only one I found with the manual aperture control specifically for a G lens. I also had a few of the 1.25 to T2 adapters spare. So I simply took the Nikon lens mount end from the extension tube set and slipped it over a 1.25 tube using a big doughnut spacer to fill the gap between the diameters and set its length to make the correct back focus required.

My final assembly measured 34.4mm depth where I need 34.0 but it appears to focus OK so I haven’t bothered removing 0.4mm. I did cut back the 1.25 tube a bit shorter so I could screw in a filter and still clear the lens mount and it’s all held together with some grub screws. It’s solid when on and easy to remove.

It also works well as an adapter for turning the lenses into spotting scopes/telescopes if you slip in an erecting eyepiece.

I ordered a replacement Fotga tube set but I got a note back from Fotga saying they’ve sold out and it would not be replenished. But they do a few Nikon G to other mount adapters that look to have the manual aperture control mount you need (I’ve ordered the Nikon to Micro 4/3 adapter, happy to risk it for £8). I think you need the (G) ones, not the (AI) ones.

Now my next plan is to actually pull my finger out and get a ZWO camera as I only borrowed one to see if it works! (thanks john78).

Cheers,

John

[Prathab]

I'm very interested in this subject. It took 4 years, but your post eventually found its audience 😀 Trying to achieve exactly this to see if I can pickup an old cooled small chip CCD camera to pair with my Nikon mount 150-600mm lens. That doughnut spacer looks like custom size and I'm not able to find it online. Could you tell me where I can source one? Thank you!

[R26 oldtimer]

I 've just modified a manual 5x1.25" filter wheel to use my mono sxv-h9 with Nikon lenses.

Perhaps this will give you some more ideas.

[Prathab]

That setup looks great! I would need aperture control (as I'm using a G lens). I've ordered one of these adapters -Fotodiox Aperture Control 52mm Filter for Nikon G/DX Lens in Reverse Mount for Macro Photography and a 52mm to 42mm Male-male coupling ring. The camera I'm considering is the OSC version of what you have. All 3 adds up to 46.5mm from sensor to flange.  

Is there enough thread room inside the starlight camera to bury one of these - https://www.firstlightoptics.com/zwo-filters/zwo-t2-to-125-filter-holder.html ?

[R26 oldtimer]

To be honest, I would not use aperture control, I would go for wide open. The aperture blades create bad diffraction spikes, so if you have to step your lens down, it is better to do so by using a front aperture mask (carton or 3d printed) or filter step-down rings.

[R26 oldtimer]

The 46,5 mm flange distance is a bit of a hassle with this camera as 17,5mm are used up in the camera. That's why I made another 2mm thick metal plate for the filter wheel instead of modifying its own 4mm thick one and gain some focus room inside and outside.

It looks like the zwo adapter with 1.25" filter will fit though.

Edited March 10, 2021 by R26 oldtimer
Added content

[Prathab]

26 minutes ago, R26 oldtimer said:

The 46,5 mm flange distance is a bit of a hassle with this camera as 17,5mm are used up in the camera. That's why I made another 2mm thick metal plate for the filter wheel instead of modifying its own 4mm thick one and gain some focus room inside and outside.

It looks like the zwo adapter with 1.25" filter will fit though.

Thank you for your input. I will let you know how I get on.

 

[Prathab]

On 10/03/2021 at 14:31, R26 oldtimer said:

To be honest, I would not use aperture control, I would go for wide open. The aperture blades create bad diffraction spikes, so if you have to step your lens down, it is better to do so by using a front aperture mask (carton or 3d printed) or filter step-down rings.

I was able to get it setup. Nikon lens+fotodiox aperture control to 52mm filter ring+52mm to T2 adapter+7.5mm t2 extension tube. Aperture control works even with my kenko 2x TC attached. I leave the aperture wide open and screw in step-down rings in the front filter ring 95mm - 77mm as you suggested. Zwo 1.25" filter adapter is on its way from China, hopefully it'll take a filter as well. Now I need to start working on my post processing skills