Helios 44-3 - mounting issue

[eddyca]

I ordered a Helios 44-3 and received yesterday. Pentax forums lens review says it was made for the Zenith which has a shorter registration distance than normal M42 and that it needs to be filed to get infinity focus. I read through the tutorial on how to do this but it seems this won't solve my specific issue. https://www.pentaxforums.com/userreviews/helios-44-3-258-mc-58mm-f2-mc.html

My issue is I cannot screw the lens in far enough for it to be centered properly and make contact with the adapter.
I think I need to find a way to extend the length of the screw in thread? It appears shorter than the other m42 lens I own.

Using the Fotodiox M42-Fx adapter on a Fujifilm X-t-3. Notice how lens is about 1cm off center.

[eddyca]

Update: I ordered the Fotodiox Lens Mount Adapter, M39 to M42 used from Amazon which is basically just a thread extender. I will report back if it solves the problem.

[D1N0]

You can use a LTM adapter plus m39 macro extension ring The 16.4mm one. Can be found in old soviet sets like these: https://www.ebay.nl/itm/174748010565?hash=item28afcb0845:g:1kQAAOSwELNgh7CV If it is m39 that is..

[jbuhler]

For a lens with a slightly shorter registration distance, instead of filing stuff I'd recommend using a helicoid adapter. Something like this:

https://www.ebay.com/itm/164763137046

You'll be able to focus to infinity because they usually go shorter than an M42 adaptor, with the plus that you'll probably be able to focus closer than the lens can go, as well.

Mount on your camera with a think FX-M42 ring.

[MartinV]

Hello, if the focus ring of your lens is making contact with the adapter, then you have the issue reported here:

http://forum.mflenses.com/helios-44-3-on-canon-eos-problem-t53877.html
EDIT: and here with a clear image: http://forum.mflenses.com/helios-44-2-and-44-3-any-difference-t60857.html

So the problem is not about registration distance as it would be with Soviet M39 SLR lenses. Your lens has the normal M42 registration distance, but the problem is that the focus ring extends a little beyond the mounting surface and binds on the adapter.

There may be a couple of solutions:
1) file down the focusing ring
2) file down the outer body of the adapter, like it's been done to the second adapter from the right in the back row of this image:

https://klaasihunt.ee/assets/img/art/jaapani-kaamerad-objektiivid/asahi-pentax-m37-m42/adapters.jpg

3) the KF M42 Pro adapter also seems to have room around the threaded part, maybe enough for the focusing ring to rotate freely.

https://www.kentfaith.com/KF06.434_new-product-kf-m10115-20-year-high-precision-lens-adapter-orange-m42-fx-pro

I have not used this type of Helios 44-3 myself, so I have no personal experience with any of the solutions.

But if the focusing ring of your lens rotates freely with the lens screwed all the way in and the only problem is that the lens is offset by a little bit, then you could just ignore it, or adjust the adapter by rotating the inner threaded portion of the adapter - but that would affect the position of other lenses you mount on the adapter.

[eddyca]

Thanks everyone! I look forward to digging into the links you've shared.