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Using Zenit-M39-mount lenses on Sony A7II?
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PostPosted: Fri Feb 10, 2017 4:44 pm    Post subject: Using Zenit-M39-mount lenses on Sony A7II? Reply with quote

I've been using M42-mount lenses quite happily with my Sony A7II and a Fotga M42 adapter. It's not the best adapter by any means, but it works just fine, and my lenses focus to infinity in the same way as when I mount them on my Pentax gear. All good.

Just recently, I've acquired my first ever M39 lenses, which were fitted to M39-mount Zenit SLRs. Since the flange focal distance for those cameras is shorter - 45.2mm vs the 45.46mm M42 standard - these lenses don't quite focus to infinity when mounted on the A7II with the Fotga M42 adapter and M39/M42 step-up ring... plus, of course, the distance scale on the focusing ring is inaccurate for the same reason.

I assume the best way to address this is to use a helicoid focusing adapter (I prefer that approach to adjusting or modifying the lenses, as I'd rather keep them original). If this is the right way to go, I assume I'd need a helicoid capable of a 27.2mm extension - since the E-mount has a flange focal distance of 18mm, and 18 + 27.2mm would give me the 45.2mm I'm looking for.

Am I on the right track here? If so, can anyone recommend a good but not-too-expensive model that is compatible with the A7II? I'm aware that some adapters will fit the NEX and early A7 cameras, but aren't compatible with the A7II's beefier mount...

Thanks in advance Smile


PostPosted: Fri Feb 10, 2017 5:14 pm    Post subject: Reply with quote

cheapest way would be getting a slim type m42-EM adapter (~2$) and some m42 extension tube (3~4$) instead of helicoid, but having a helicoid would be much more useful later for other exotic lens.


PostPosted: Fri Feb 10, 2017 10:37 pm    Post subject: Reply with quote

Thanks for the tip... The only thing that confuses me with that approach is being able to source an M42 extension tube of the right length to go on an adapter. Am I missing something?


PostPosted: Wed Feb 15, 2017 2:58 pm    Post subject: Reply with quote

BigMackCam wrote:
Thanks for the tip... The only thing that confuses me with that approach is being able to source an M42 extension tube of the right length to go on an adapter. Am I missing something?


you need 26mm (1mm is thickness of the adapter) extension but you can use less than 26 and you just lose some mfd distance. its not a big deal. helicoid make things easier for sure. also you can place some rubber between extension and adapter to prevent it screwed all the way in and get the exact length in total that you want.


PostPosted: Wed Feb 15, 2017 6:15 pm    Post subject: Re: Using Zenit-M39-mount lenses on Sony A7II? Reply with quote

BigMackCam wrote:
I've been using M42-mount lenses quite happily with my Sony A7II and a Fotga M42 adapter. It's not the best adapter by any means, but it works just fine, and my lenses focus to infinity in the same way as when I mount them on my Pentax gear. All good.

Just recently, I've acquired my first ever M39 lenses, which were fitted to M39-mount Zenit SLRs. Since the flange focal distance for those cameras is shorter - 45.2mm vs the 45.46mm M42 standard - these lenses don't quite focus to infinity when mounted on the A7II with the Fotga M42 adapter and M39/M42 step-up ring... plus, of course, the distance scale on the focusing ring is inaccurate for the same reason.

I assume the best way to address this is to use a helicoid focusing adapter (I prefer that approach to adjusting or modifying the lenses, as I'd rather keep them original). If this is the right way to go, I assume I'd need a helicoid capable of a 27.2mm extension - since the E-mount has a flange focal distance of 18mm, and 18 + 27.2mm would give me the 45.2mm I'm looking for.

Am I on the right track here? If so, can anyone recommend a good but not-too-expensive model that is compatible with the A7II? I'm aware that some adapters will fit the NEX and early A7 cameras, but aren't compatible with the A7II's beefier mount...

Thanks in advance Smile


The best and "perfect" solution is to go for a Zenit M39 4 ring set (cheaply available from Russia) and a M39/LTM to NEX adapter (cheaply available from China).
The Zenit ring set includes a 16.4mm distance ring which is exactly the difference between M39/LTM (28.8mm flange focal distance) and Zenit M39 (45.2mm). Obviously this was done to enable the usage of Zenit/M39 lenses on the old Russian M39/LTM cameras like the Zorkis and FEDs.
My old Zenit/M39 lenses work perfectly at infinity with this solution.


PostPosted: Wed Feb 15, 2017 6:40 pm    Post subject: Reply with quote

The perfect solution which enables exactly the needed 45.2 mm flange focal distance:

Camera + M39 to NEX adapter + 16.4 mm Zenit distance ring + lens:



PostPosted: Sat Feb 18, 2017 7:52 pm    Post subject: Reply with quote

Ah! The extension ring solution is *perfect*! This is exactly what I need. Thank you so much, guys Smile

EDIT: ... and a set of four M39 rings inc. 16.4mm just ordered - thanks again!