Adapters to achieve back focal distance between camera lens and zwo 1600mm + EFW

[HeavyT]

Hi folks

In a world of pain trying to try out my 1600mm pro with a Nikon lens.
I picked up the ZWO Nikon adapter
I picked up an old Nikon lens with manual aperture adjustment ring
I've brought the spacing in as close as I can using a little adapter ring inserted in to the ZWO adapter and a male to male m42 adapter between that and the filter wheel.

It got me close, but I still needed to stop down to about f/11 before I could focus on infinity.

My last thing to try is a $60 m54 female to m42 male adapter if I can get one, but it would take out 2mm of back focus at maximum.

Is this a losing battle? Has anyone been able to make this work?

What's left of my hair is falling out.

Thanks in advance for your suggestions.

[HeavyT]

Despite having been confident I'd purchased the correct adapter I discovered this morning I had not.

[JA]

Hi HT,

If you have an old manual Nikon lens most likely it's a Nikon F mount lens which has a 46.5mm flange focal distance. (if it's a cine or enlarger lens then the FFD is not 46.5mm)

Taking it as an F mount lens (the most probable) and given you have a 1600mm (backfocus = 6.5mm) and the 11 mm ZWO supplied black spacer, then you need a further spacer with thickness equal to.....

46.5 - (6.5 +11) = 29mm

29mm is the thickness of the ZWO to Nikon F mount adapter I have - the filter drawer type.
See... https://www.bintel.com.au/product/zwo-filter-drawer-nikon/?gclid=EAIaIQobChMI7o3124-49gIVTCUrCh2vvQftEAQYAiABEgJpAvD_Bw E

There is also a ZWO to Nikon F mount adapter - screw in filter type with the same 29mm thickness. It also has an extra 5mm spacer which you don't use with the 1600mm.See...https://www.bintel.com.au/product/zwo-nikon-t2-ii-adapter/?gclid=EAIaIQobChMIgcmcp5C49gIVYZhm Ah2AfwZmEAQYASABEgIq6fD_BwE

There is also a much thinner Nikon lens adaptor to use between a Nikon Lens and ZWO filter wheel. Without the filter wheel the spacing would be incorrect. Perhaps that's the type you have tried to use and couldn't get focus.

Best
JA

[muletopia]

G'day HT.
Just figure out what thickness you need and its attachment method and get Joshua Bunn to make you one.
Chris