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Beware when "fixing" tamron adaptall M42 mount
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PostPosted: Mon Jun 04, 2007 2:20 pm    Post subject: Beware when "fixing" tamron adaptall M42 mount Reply with quote
I got my Tamron SP 60-300mm yesterday. I came with a Nikon mount, which is fine for my analogue Nikon EM, but my digital Pentax needs either K mount or screwmount.

So I bought me a cheap 80-210 on ebay with Pentax screw mount adapter. That one arrived today.

It fitted on the 60-300mm, but I noticed it could only use the "auto' mode of the screwmount, since there is no M/A switch. Basivly I could only use the lens wide open.

now, my solution was: just put a tiny drop of glue on top of the pin, and the problem would be solved!

That's where the problems began. I took the mount off the lens, pushed the pin in comlpetely and held it in trough the other side of the mount. I glued it, and the pin stayed down, perfect.

Now I wanted to put the mount on the lens again, but to play it safe, I tried it on the cheapo 80-210 first. Am I glad I did that...because the mount did not want to "click" into position! I figured: "must be the lever pushed up too high" and tried to force it a little..."click" there it was! The mount was on there and the aperture closed nicely from 3.8 to 32

End of story, right? All I needed to do then was take off the mount again and put it on my 60-300
Well, due to the little "fix" I did, I could take the mount off the lens anymore! The lever on the inside of the mount was pushing against the aperture lever of the lens itself.

I got the screwdriver out and did the onyl thing I could think of, take the mount apart.
Luckily, this worked. And was able to take the mount off after unscrewing the 3 screws.

Now, I still wanted this thing to work, but the damn pin was glued in so tightly, the mount had become useless.

I tried pulling the pin back out with a grip, but could onyl move it bit by bit.

eventually after a lot of experimenting the mount would go back on the lens, with the pin sticking out of the screwmount with about 1mm.
To my surprise, the aperture closed ad opened fully !

So I messed up the mount pretty bad (to a point where i can never get it back into original state) but the good news is I can at least use it on my lenses...

I ran into some other problems with that 80-210 after that, but I'll post that in a different topic.


Conclusion: if you want to "fix" an adpatall screw mount, DO NOT PUSH IN THE PIN COMPLETELY. Leave about 1 mm and you should be fine...

Tom


PostPosted: Mon Jun 04, 2007 2:28 pm    Post subject: Reply with quote
I've fixed this problem easily.
I've blocked with a piece of plastic the lever inside the lens.
Everything works as it should be.


PostPosted: Mon Jun 11, 2007 11:31 pm    Post subject: Reply with quote
I don't need to do anything now I have a Pentax but I used to use Tamron with M42 on Minolta and Sony. To keep the pin in I used to fold up a strip of insulating tape and push it under the bar on the Tamron mount. this did the job and allowed a little bit of movement to tighten everything up. I never had a 'Bit of tape' fall out or stop working and I would always be swapping mounts between lenses. No problem at all.


PostPosted: Tue Jun 12, 2007 6:42 am    Post subject: Reply with quote
I´m not sure, but I think it would be easier to remove the pin completely. I did that on a Zenitar 16mm and i works perfect.


PostPosted: Tue Jun 12, 2007 9:32 am    Post subject: Reply with quote
lahnet wrote:
I´m not sure, but I think it would be easier to remove the pin completely. I did that on a Zenitar 16mm and i works perfect.


That Idea isn’t applicable to a Tamron Adaptall lens, although it would be no problem to remove the pin from the M42 mount if were fouling any part of the camera. However that would still not close the lens aperture for full manual stop use
Removing the pin from an ordinary M42 lens is an easy option as long as you can put it back. Also not a alternative for those who wish to use their M42 lenses on a film camera.


PostPosted: Mon Jun 18, 2007 3:27 am    Post subject: Re: Beware when "fixing" tamron adaptall M42 mount Reply with quote
TDN wrote:
I got my Tamron SP 60-300mm yesterday. I came with a Nikon mount, which is fine for my analogue Nikon EM, but my digital Pentax needs either K mount or screwmount.

So I bought me a cheap 80-210 on ebay with Pentax screw mount adapter. That one arrived today.

It fitted on the 60-300mm, but I noticed it could only use the "auto' mode of the screwmount, since there is no M/A switch. Basivly I could only use the lens wide open.

now, my solution was: just put a tiny drop of glue on top of the pin, and the problem would be solved!

That's where the problems began. I took the mount off the lens, pushed the pin in comlpetely and held it in trough the other side of the mount. I glued it, and the pin stayed down, perfect.

Now I wanted to put the mount on the lens again, but to play it safe, I tried it on the cheapo 80-210 first. Am I glad I did that...because the mount did not want to "click" into position! I figured: "must be the lever pushed up too high" and tried to force it a little..."click" there it was! The mount was on there and the aperture closed nicely from 3.8 to 32

End of story, right? All I needed to do then was take off the mount again and put it on my 60-300
Well, due to the little "fix" I did, I could take the mount off the lens anymore! The lever on the inside of the mount was pushing against the aperture lever of the lens itself.

I got the screwdriver out and did the onyl thing I could think of, take the mount apart.
Luckily, this worked. And was able to take the mount off after unscrewing the 3 screws.

Now, I still wanted this thing to work, but the damn pin was glued in so tightly, the mount had become useless.

I tried pulling the pin back out with a grip, but could onyl move it bit by bit.

eventually after a lot of experimenting the mount would go back on the lens, with the pin sticking out of the screwmount with about 1mm.
To my surprise, the aperture closed ad opened fully !

So I messed up the mount pretty bad (to a point where i can never get it back into original state) but the good news is I can at least use it on my lenses...

I ran into some other problems with that 80-210 after that, but I'll post that in a different topic.


Conclusion: if you want to "fix" an adpatall screw mount, DO NOT PUSH IN THE PIN COMPLETELY. Leave about 1 mm and you should be fine...

Tom


Thanks for the warning Tom. With my 400D I normally use the type of M42/EOS adapter with the flange for keeping the pin depressed, so this problem hasn't arisen for me (yet!).

But I think with your Pentax camera it would probably be a much better idea for you to use the K or KA type Adaptall mounts. You'll know more about modern Pentax cameras than me, but I can confirm that the K-mount Adaptall mount allows fully open aperture metering on my ME Super, just like a Pentax lens.


PostPosted: Fri Oct 28, 2011 4:13 pm    Post subject: Re: Beware when "fixing" tamron adaptall M42 mount Reply with quote
TDN wrote:
I got my Tamron SP 60-300mm yesterday. I came with a Nikon mount, which is fine for my analogue Nikon EM, but my digital Pentax needs either K mount or screwmount.

So I bought me a cheap 80-210 on ebay with Pentax screw mount adapter. That one arrived today.

It fitted on the 60-300mm, but I noticed it could only use the "auto' mode of the screwmount, since there is no M/A switch. Basivly I could only use the lens wide open.

now, my solution was: just put a tiny drop of glue on top of the pin, and the problem would be solved!

That's where the problems began. I took the mount off the lens, pushed the pin in comlpetely and held it in trough the other side of the mount. I glued it, and the pin stayed down, perfect.

Now I wanted to put the mount on the lens again, but to play it safe, I tried it on the cheapo 80-210 first. Am I glad I did that...because the mount did not want to "click" into position! I figured: "must be the lever pushed up too high" and tried to force it a little..."click" there it was! The mount was on there and the aperture closed nicely from 3.8 to 32


This cannot happen with Sigma DSLR's when a proper M42-SA adapter is used because proper M42-SA adapters have a built in flange in their base to compress the pin as the adapter is screwed on to the lens. Cheap Chinese made M42-PK adapters, which can also fit on the SA mount, dont have this flange, nor do M42-Nikon adapters...I suggest you write to the manufacturers of your adapter and ask them to change the design to include such a built in flange. Wink


PostPosted: Fri Oct 28, 2011 10:04 pm    Post subject: Reply with quote
This is very easy to fix.
I had the same problem, when I put in a metal clip to keep the auto mechanism "manual"
I could not remove the adapter.

It is however quite easy to disassemble, just unscrew the screws in the mount and you can fix the problem.

The best fix, as mentioned, is to get an adapter that presses the M42 pin. These are quite common now.
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