Introduction: ZENITH Helios 44m (M42) to Nikon F Mount Conversion.

Found some old bashed Zenith Helios 44M lenses so wondered if I could use them on my Nikon gear..
Quick browsing left me with few findings.
1 . obviously you need an adapter.
2. other cameras can work with M42 lenses through adapters no problem, Nikon has deeper focal plane therefore once using adapter there is no room to get a lens deep enough to focus at infinity.
3. Its possible to focus at infinity if you purchase ridiculously( comparing to lens value) expensive adapter with reducing lens on its back. you get what you pay for...meaning, cheap one has poor quality lens which messes everything up, even expensive one isn't flawless .
4. I have read somewhere that because of focal plane, even if you get to focus to infinity, lens goes so deep that you would crush your mirror once firing.

I think nah....

So I have 3 Zenith Helios 58/2 44M (I bought 2 cameras on car-boot sale for 2 quid each for my 2 years old back then to keep him away from my gear). All of them survived 2 years with my kid (Gniotsja nie lamiotsja- common decryption for everything from CCCP meaning bending but not breaking).
Welcome to my Butcher style conversion.

Step 1:

Metal epoxy putty
Dremel tool with few attachments
2 drill bits
sand paper
vernier caliper
Nikon F lens mount ring (male) with screws.

Step 2:

Step 3:

For the purpose of this task you have to be sure you own Helios 58/2 44m which looks like the one on the picture.

Step 4:

Take A/M selector cover off by removing 3 screws (one by  silver selector (4th) can stay as it doesn't hold into the lens body)

Step 5:

This is what we have after removal
I used rubber band to hold aperture lever in closed position so aperture ring can do its job. You can tape it up, glue it etc. knock yourself out.

Step 6:

most important bit : distance ring. It looks ugly but it does its job. I have chosen epoxy putty instead of some plastic sheet or alloy . reasons for this are simple:
1. didn't know how thick it should be apart from general idea by holding the lens to my test (have some old cheap  Nikon slr) camera.
2. cheap
3. quick and easy to work with including sanding
4. had it at home
5. couldn't be bothered if it looks nice or not- it was test and trial - once getting everything right I might machine something nice out of alloy.

ring has to be at least as wide as the body of the lens (to hold aperture ring secured) and wide enough to fit Nikon lens ring which is narrower than lens itself. It also needs to be thick just about bit more than 3mm. Its 3mm+ after sanding so allow some excess while molding.

1. use some cream ( I used Nivea cream) on removed part of the lens, cover flat part around the thread which will stop the putty from sticking into it.
2 cover F mount ring with a cream as well for same purpose.
3. mix putty and roll it making a roll which will be long enough to create a ring along removed lens part edge (and remember about thickness).
4. place putty on removed part making sure both ends join seamlessly  into one piece to avoid splitting the ring later on.
5. put F mount on the top of that and press
6 . try to position F mount ring parallel to bottom part.

Step 7:

Once hardened you can start working on it.
1.Sand it - mine is about 3.14mm (trial and error)
2. Drill 3 holes to screw it into the lens (remember screws needs to go flush with the ring, I used original screws which I shortened with dremel cutting disc.
3. drill holes for F mount ring ( remember to position F mount ring so lens will be centered and focusing mark of the lens will be in the middle once looking at camera from the top).

Step 8:

install distance ring on the lens

Step 9:

ring won't be straight for sure which in my case worked OK because armed with vernier caliper and running it around I was able to set up the plane ( ish ;) )by tightening F mount screws.

Step 10:

I found out that I went a tad sand paper happy too much and made it too thin. Luckily I had some focusing adjustment spacers... off some old broken lens I purchased for parts. by sanding it too much I actually passed infinity point therefore I was achieving it before hard stop of the lens ( by the cost of extending closest focusing distance).
Please notice that small area on the epoxy ring painted blue- I will explain it later.

Step 11:

this is how it looks like after finishing.

Step 12:

getting back to step 10, that small painted area...
As you can see from the picture in this step camera's aperture ring isn't actuated as lens is missing a prong to hook up into it.
In the future once I will find smaller drill bit I am about to cut that piece of epoxy ring and drill aperture ring to insert some small pin to actuate aperture ring of the camera.
I am not sure if it will work as increments might be different for Helios comparing to Nikon lens but it would be nice to be able to use this lens in Aperture mode not only Manual.
theoretically it would be possible to mate lens aperture with aperture lever of the camera... however... I am lazy not crazy. ;)

Thanks for watching... and you know.... don't laugh ... it works ;) and took me less than 2h to make ;).

Step 13:

fine exposure tweeaking would probably give a better colours for helios, but sharpness was a goal here.

Step 14:

100% crop focused to infinity (hard stop)

Step 15:

Some of bokeh, colour rendition and DOF test pictures.
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