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Infinity problem-resolved .
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PostPosted: Wed Aug 11, 2010 4:52 pm    Post subject: Infinity problem-resolved . Reply with quote
Vemar Tele-Auto 135mm f3.5 in M42:




This lens looks like its in great shape- Does not look like its ever been opened,no obvious marks of repair. The focus ring is smooth and the aperture works perfectly.No loose moving parts inside. I was surprised to find that it does not focus to infinity. Anybody have any ideas/suggestions/experience why?
What happens here is when I focus to 15 ft. focus is good then its a blurr,as I go towards infinity.This same thing happens at different distances above 15ft.
I am hoping that I will have enough ideas -before I open this for repars.

Thanks

Last edited by Kathmandu on Sun Aug 22, 2010 1:26 am; edited 2 times in total


PostPosted: Wed Aug 11, 2010 5:04 pm    Post subject: Reply with quote
Are you positive that this is M42 and not T-Mount?

Hold on, scratch that, if it were T mount it would focus to infinity, but not close up. Sorry - my confusion. Rolling Eyes


PostPosted: Wed Aug 11, 2010 5:46 pm    Post subject: Reply with quote
Doesn't it focus to inf. on an EOS or on an M42-cam?


PostPosted: Wed Aug 11, 2010 6:05 pm    Post subject: Reply with quote
I'm using a M42 to Sony adapter and using it with a Sony DSLR. The mount may not be the problem- its inconsistent as far as how far I can focus-sometimes 15 ft sometimes 40ft- but then it blurrs out and never reaches infinity. Thank you both for your inputs. Its a wierd problem I have never seen before.


PostPosted: Wed Aug 11, 2010 6:46 pm    Post subject: Reply with quote
You should test it on am M42-cam, then.


PostPosted: Wed Aug 11, 2010 7:10 pm    Post subject: Reply with quote
Kathmandu wrote:
I'm using a M42 to Sony adapter and using it with a Sony DSLR. The mount may not be the problem- its inconsistent as far as how far I can focus-sometimes 15 ft sometimes 40ft- but then it blurrs out and never reaches infinity. Thank you both for your inputs. Its a wierd problem I have never seen before.


Sounds like there must be something loose inside. Inconsistent behaviour on the same body and adapter can't be anything else?


PostPosted: Wed Aug 11, 2010 7:14 pm    Post subject: Reply with quote
LucisPictor wrote:
You should test it on am M42-cam, then.


I did test it on a Yashica TL Electro X-and the symptoms are the same. I did notice something peculiar in that when I hold the camera and lens (both the M42 camera and Sony), and gradually bring it up to shooting height(i.e. horizontal position)-I get infinity. If I hold the camera and lens pointing to the sky and bring it down gradually to shooting straight (i.e. horizontal position), I loose infinity.

If I hold the lens pointing upwards in anyway the weight of the elements, or something inside must be shifting making it looses infinity-Looks as though I may have to open it up.

Regards Very Happy


PostPosted: Sun Aug 22, 2010 1:11 am    Post subject: Reply with quote
Quote:
This lens looks like its in great shape- Does not look like its ever been opened,no obvious marks of repair. The focus ring is smooth and the aperture works perfectly.No loose moving parts inside. I was surprised to find that it does not focus to infinity. Anybody have any ideas/suggestions/experience why?
What happens here is when I focus to 15 ft. focus is good then its a blurr,as I go towards infinity.This same thing happens at different distances above 15ft.
I am hoping that I will have enough ideas -before I open this for repars.


That was my post a few days ago- and I grudgingly took the lens apart-to see what was causing the intermittent infinity focus problems. This lens was difficult putting back together-I spent about about 6 hrs in a span of 6 days just trying to figure out how it assembled back together(a lot of time just staring at it)-not having taken the extra time to document and take pictures of the disassembling.
Today I had a breakthrough and the helical screwed together perfectly. The culprit to my intermittent infinity problem was the second element in the front cell;the ring holding it in had unscrewed a tad allowing that particular element to move ever so slightly every time I pointed the camera up or down. It works great now- Smile

Pictures taken after final assembly :






PostPosted: Sun Aug 22, 2010 10:19 am    Post subject: Reply with quote
Congrats witrh your result and with your patience to get the lens properly mounted again!


PostPosted: Sun Aug 22, 2010 4:02 pm    Post subject: Reply with quote
Thanks Minolfan-its like finishing a puzzle sometimes-Its definitely a test/exercise in patience and perseverance although that may not have been the objective initially .I have 2 Vemars now with the serial number beginning with "H"-and I love their image quality, and clarity even wide open.Lens hoods complement them well.
The images above except for the last one(shot at f 5.6) are all wide open @f3.5. The min. focus distance is 6ft. I think this would make a super potrait lens.
Jims camera in Seattle(he is on the web) has the same lens maybe in better shape for $39,if anyone wants to grab one-I did not see another similar one anywhere on the wild web.
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