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03-26-2019, 01:27 PM   #1
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Does an M42 adapter work with all M42 lenses?

I've been looking into getting my friend an M42 screw mount adapter for her Canon 600D so that she can use her film camera's lenses on it.

So far, my understanding is that there are a few variations in M42 lenses that have an auto-aperture setting, and that I may need different adapters to retain full functionality of them.

Is this something I need to be considering, or is it mostly a non-issue?

I'm guessing that most auto-aperture lenses have a manual setting, so whether or not the aperture can be set shouldn't be a problem, right?

Thanks!

03-26-2019, 02:00 PM - 1 Like   #2
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I'd be more concerned with the different brands/ types of M42 adapters...
03-26-2019, 02:08 PM   #3
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QuoteOriginally posted by Ropuchy Quote
I've been looking into getting my friend an M42 screw mount adapter for her Canon 600D so that she can use her film camera's lenses on it.

So far, my understanding is that there are a few variations in M42 lenses that have an auto-aperture setting, and that I may need different adapters to retain full functionality of them.

Is this something I need to be considering, or is it mostly a non-issue?

I'm guessing that most auto-aperture lenses have a manual setting, so whether or not the aperture can be set shouldn't be a problem, right?

Thanks!
Your first sentence says you are concerned about her using lenses she already has on a camera she already has.
Making that work would be my goal.
03-26-2019, 02:09 PM   #4
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QuoteOriginally posted by pepperberry farm Quote
I'd be more concerned with the different brands/ types of M42 adapters...
I've been looking at Fotodiox adapters with the focus confirmation chip.

---------- Post added 03-26-19 at 02:11 PM ----------

QuoteOriginally posted by reh321 Quote
Your first sentence says you are concerned about her using lenses she already has on a camera she already has.
Making that work would be my goal.
Right. She has an M42 mount film camera with lenses, and I'm looking into getting her an adapter to allow those lenses to be used on her DSLR.

03-26-2019, 02:17 PM - 1 Like   #5
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FYI

https://www.instructables.com/id/M42-Lens-Aperture-Control-on-Modern-DSLRs/
03-26-2019, 02:18 PM   #6
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QuoteOriginally posted by reh321 Quote
Your first sentence says you are concerned about her using lenses she already has on a camera she already has.
Making that work would be my goal.
I see what you mean now, sorry.
It's not just the M42 lenses from her film SLR that I'd like to work, but also potentially other lenses in the future.
I suppose my question is more "Can I expect M42 lenses to adapt in general" and not "Do these specific lenses adapt"
03-26-2019, 02:23 PM - 2 Likes   #7
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Some m42 lenses have a pin that needs to be pushed in to use the aperture. My mamiya 50 is one. I hot glued it pushed in. All my takumar lenses have a manual/auto switch which overrides this. It's easy to check if you have the lenses by looking if turning the ring closes it down off camera without pushing the pin. Of course a m42 to canon might not matter anyway. You don't need a flush adapter because of Canon's shorter registration distance.
Edit
I failed to mention some have a tiny pin that needs depressing to switch from auto/manual when off camera where the lens meets the mount.


Last edited by swanlefitte; 03-26-2019 at 02:31 PM.
03-26-2019, 02:26 PM - 1 Like   #8
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Thank you for the link, very informative!

---------- Post added 03-26-19 at 02:29 PM ----------

QuoteOriginally posted by swanlefitte Quote
Some m42 lenses have a pin that needs to be pushed in to use the aperture. My mamiya 50 is one. I hot glued it pushed in. All my takumar lenses have a manual/auto switch which overrides this. It's easy to check if you have the lenses by looking if turning the ring closes it down off camera without pushing the pin. Of course a m42 to canon might not matter anyway. You don't need a flush adapter because of Canon's shorter registration distance.
Do you know if an adapter that is designed to allow the 'pinned' lenses to function well would also work with auto/manual and fully manual lenses?
Thanks for the info!
03-26-2019, 02:33 PM - 1 Like   #9
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You just need an adapter that has a flange that can push the aperture pin on non auto/manual switch lenses. Good news is most EOS/M42 adapters I've seen have this flange, so no worries. The best you can get is the one with the confirmation chip, so you can make full use of the focus system on the camera as an aid.

As a side note: All lenses will also show as being "50mm" in the EXIF data, since that's the most common focal length and fixing that requires a custom chip and adapter for every lens. Expensive, but doable.

03-26-2019, 02:37 PM - 2 Likes   #10
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QuoteOriginally posted by Ropuchy Quote
Do you know if an adapter that is designed to allow the 'pinned' lenses to function well would also work with auto/manual and fully manual lenses?
Thanks for the info!
Yes, the issue is actually the other way around. A/M lenses work on any M42 adapter, but non A/M switch lenses can only be shot wide open, unless you find a way to depress the pin.



03-26-2019, 02:39 PM - 1 Like   #11
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QuoteOriginally posted by Ropuchy Quote
Thank you for the link, very informative!

---------- Post added 03-26-19 at 02:29 PM ----------


Do you know if an adapter that is designed to allow the 'pinned' lenses to function well would also work with auto/manual and fully manual lenses?
Thanks for the info!
It stops auto which prevents focusing wide open and flipping the switch to the preselected fstop. It's hard to focus at dark f11. Thus focusing wide open and then dialing in f11 requires taking your eye away or remembering how many clicks to get to f11 you might lose focus during that time. With being able to use the switch you focus shift and click.
03-26-2019, 02:41 PM   #12
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QuoteOriginally posted by torashi Quote
You just need an adapter that has a flange that can push the aperture pin on non auto/manual switch lenses. Good news is most EOS/M42 adapters I've seen have this flange, so no worries. The best you can get is the one with the confirmation chip, so you can make full use of the focus system on the camera as an aid.

As a side note: All lenses will also show as being "50mm" in the EXIF data, since that's the most common focal length and fixing that requires a custom chip and adapter for every lens. Expensive, but doable.
Alright, so would an adapter with a proper flange work with all lenses with an aperture pin?
The Fotodiox adapter that I'm looking at has 2 versions, one for Takumar and Zeiss lenses, and the other for Pentacon and Tomoika Cosina lenses.

amazon.com : Fotodiox Pro Lens Mount Adapter Compatible with M42 Type 1 Screw Mount SLR Lens to Canon EOS (EF, EF-S) Mount D/SLR Camera Body - with Gen10 Focus Confirmation Chip : Camera & Photo?tag=pentaxforums-20&

Thank you for the extra info on the EXIF data!

---------- Post added 03-26-19 at 03:00 PM ----------

QuoteOriginally posted by swanlefitte Quote
It stops auto which prevents focusing wide open and flipping the switch to the preselected fstop. It's hard to focus at dark f11. Thus focusing wide open and then dialing in f11 requires taking your eye away or remembering how many clicks to get to f11 you might lose focus during that time. With being able to use the switch you focus shift and click.
Ah, alright.
So an adapter that depresses the pin will make the lens fully manual, but an adapter that doesn't allows you to use the A/M switch to focus wide open and then switch to manual and shoot at the selected aperture?

Last edited by Ropuchy; 03-26-2019 at 02:53 PM.
03-26-2019, 03:01 PM - 1 Like   #13
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The flange won't push the pin because the pin is inside the screw part. Some lenses on canon might need modification because the pin can hit the mirror. That is worth checking.
03-26-2019, 03:08 PM - 1 Like   #14
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Here is an article on that but you can Google it.
How to Eliminate Mirror Hang with a SMC Takumar 50mm f/1.4 - DustinAbbott.net
03-26-2019, 03:10 PM   #15
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QuoteOriginally posted by swanlefitte Quote
The flange won't push the pin because the pin is inside the screw part. Some lenses on canon might need modification because the pin can hit the mirror. That is worth checking.
Oh ok.
Yeah, there are issues with that on some early Canon FF cameras. It shouldn't be a problem on a crop or modern FF from them, though. Thanks for the heads-up, though!
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