Short helicoid for Nikon Z mount?

[Jack Dahlgren]

Looking for recommendations on a short helicoid to obtain infinity focus with lenses like Nikkor “O” and similar. I mostly find them to allow macro focus and not seeing many with native Z camera mount.

A solution with adapters is OK, but would prefer Z mount on camera side and F or M42 on lens side.

[ianwatson]

Rafcamera.com has a flat M42 to Z mount adapter. You could then try a Borg helical focuser which has the appropriate M42 mounts at the ends.

[MEPER]

I found a thread here discussing the topic but don't know if it is of any value:
http://forum.mflenses.com/nikkor-o-55mm-f12-how-to-focus-t80927.html

The Nikkor "O" is the Oscilloscope Nikkor (55/1.2)?

[Birna Rørslett]

Very easy to make the required adapter. I have made many of them over the last couple of years.

For example, a flat M42-Z adapter, then add a short M42 helicoid of a decent quality, for example, one with a brass core. Still these are very decently priced. The flat adapters are dispersed among the usual M42-Z items so you have to scan for them, but since they look so different they are not hard to identify. I have seen them at ridiculously low prices too.

At the front end, put any mount you require. For the 55mm f/1.2 Nikkor-O (aka 'CRT' or 'Oscilloscope' Nikkor), you just need the ubiquitous 42-39mm small ring.

[Birna Rørslett]

I knew I had posted a photo relevant to this discussion recently. Found it, see below.



Here are two examples of small focusing adapters for my old Fisheye-nikkors. Put the 42-39mm adapter ring in front instead of the F bayonet, and you are all set to explore the world through the eye of the 55/1.2 Nikkor-O. Spoler alert: it will focus to infinity, but you will quickly learn this is not a purpose for which  the lens was designed. Still fun to use and the DX-format Z range like the Z fc chucks out more of the poor corners

The legendary Rodenstock 100mm f/1.6 is another of those lenses that can find a new life of existence on the Z system. You will need a wider helicoid for this lens, though, as it is more beefy. I used a 65mm size for this lens. It will focus to infinity with ease and almost covers the FX format with excellent rendition. Only the extreme corners tend to go softer, but can easily be cropped off.

[Akira]

Rafcamera.com has a flat M42 to Z mount adapter. You could then try a Borg helical focuser which has the appropriate M42 mounts at the ends.

Currently, the M42 helicoids are removed from BORG official website.  The BORG Z-mount adapter is thicker than the Z to M42 adapter by Rafcamera and needs an extra 49.8mm P0.75 to M42 adapter ring.  The adapter ring has a flange which is roughly 1mm thick.  The total thickness of both parts is not indicated in the website.  The infinity focus can be hindered with the BORG parts depending on the thickness of the helicoid you use.

[Birna Rørslett]

I would suggest any interested opt for the standard flat M42-Z adapters, which are both cheap and not that hard to find on eBay.

Here is a typical example to give an idea what to look for,

https://www.ebay.co.uk/itm/254677608107

At such rock-bottom prices you easily purchase a handful of these and just epoxy glue the adapter to the helicoid. I love doing such nerdy stuff

By the way, it may be difficult to get anything at present from RAFCamera as they are based in Russia.

[ianwatson]

Currently, the M42 helicoids are removed from BORG official website. 

I found them here. Is this not the official site?

https://sciencecenter.net/hutech/prices/borgparts/html/7842.htm

The BORG Z-mount adapter is thicker than the Z to M42 adapter by Rafcamera and needs an extra 49.8mm P0.75 to M42 adapter ring.  The adapter ring has a flange which is roughly 1mm thick.  The total thickness of both parts is not indicated in the website.  The infinity focus can be hindered with the BORG parts depending on the thickness of the helicoid you use.

Thank you for the the warning. I had not found BORG's Z-mount adapter and so have a couple of flat M42-Z adapters on order from Rafcamera. I will more urgently seek some of BORG's helicoids, just in case they are not so easy to obtain.

[ianwatson]

I would suggest any interested opt for the standard flat M42-Z adapters, which are both cheap and not that hard to find on eBay.

The thread on adapters has left me leery of "mystery meat" products. Are there any particular suppliers whom you favour?

By the way, it may be difficult to get anything at present from RAFCamera as they are based in Russia.

They have been posting news of shipments and delays. It seems that one can still obtain their products but there will be a longer wait. They offer a refund if one does not receive one's order in 3 months. I have a few items on order and will keep you posted.

[Akira]

I found them here. Is this not the official site?

https://sciencecenter.net/hutech/prices/borgparts/html/7842.htm

Thank you for the the warning. I had not found BORG's Z-mount adapter and so have a couple of flat M42-Z adapters on order from Rafcamera. I will more urgently seek some of BORG's helicoids, just in case they are not so easy to obtain.

Ian, Hutech is the authorized dealer of BORG products for the U.S.  The dealers and shops may still have the M42 helicoids in stock.

The Nikon Z-mount adapter has just been released from BORG (not cheap!):

https://www.tomytec.co.jp/borg/products/partsDetail/summary/756

You also need this 49.8mm to M42P1 adaptor ring along with the camera mount to use your M42 gadgets:

https://www.tomytec.co.jp/borg/products/helicoidDetail/summary/47

The texts are only in Japanese, but you can click each thumbnail of the product to enlarge to get a general idea of the thickness of the adapter.

[Akira]

I hope this would be of any help to get the general idea of BORG camera mouts and 49.8-42mm adapter.  (The mounts in the image are for Sony E and m4/3, by the way.)

[Jack Dahlgren]

The legendary Rodenstock 100mm f/1.6 is another of those lenses that can find a new life of existence on the Z system. You will need a wider helicoid for this lens, though, as it is more beefy. I used a 65mm size for this lens. It will focus to infinity with ease and almost covers the FX format with excellent rendition. Only the extreme corners tend to go softer, but can easily be cropped off.

This is the lens which sparked the idea for me. Now to find all the parts.

[Birna Rørslett]

Here is the b/w version of a photo posted earlier on NG, showing the Rodenstock 100/1.6 with its beefy focusing adapter on my Z fc.

I already had a big 65mm helicoid that was put to use for this project, but one might be able to do with 58mm helicoids as well.  For my adapter, I epoxy glued a factory Z bayonet to the end of the helicoid. Were I to repeat the adaptation, I probably stick to 58mm and use 58->42 >Z at the rear, 58->48 in front (since my Rodenstock has 48mm thread on its rear end). If 52mm-based helicoids exist, they might be useful but no guarantee from my side the Rodenstock fits inside.

[ianwatson]

Ian, Hutech is the authorized dealer of BORG products for the U.S.  The dealers and shops may still have the M42 helicoids in stock.

Thank you, Akira. Hutech tells me that the M42 helicoids have been discontinued. None of their dealers has them.

So it seems that a shot in the dark on eBay is in my future.

[ianwatson]

By the way, it may be difficult to get anything at present from RAFCamera as they are based in Russia.

I ordered a few things from them on 7th April. They arrived this morning. Not bad at all, considering.