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Samyang 135mm f2 cannot reach infinity focus 6D

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#1 elakrab

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Posted 22 October 2019 - 11:10 PM

Hi,

 

I just got a Samyang 135mm f2 and ... big bummer, the focus cannot reach infinity by really little :( :(  

 

I know that in many cameras there are some focusing adjustment screws hidden in the focusing rubber or somewhere else. Is that the case of the Samyang/Rokinon? Anyone has manipulated those to move the focusing a bit to allow infinity focus? 

 

Big thanks



#2 B 26354

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Posted 23 October 2019 - 12:32 AM

Doesn't sound right, to me. I've never encountered a standard camera lens that couldn't focus at infinity... and these days, digital-camera lenses reach focus beyond infinity. If you bought it new... return it for a replacement. If you bought it used... return it for a refund.



#3 elakrab

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Posted 23 October 2019 - 01:00 AM

Nevermind, I just did some quick surgery on the samyang and now it focuses correctly to infinity as it is supposed to be without the stopper getting in the middle :) . The procedure is similar to the one for their 85mm and other manual prime lenses. Not the first lens I have to do this to but definitely one of the easiest ones https://www.dyxum.co...topic76615.html

 

So, instructions:

 

1) Peel the rubber out 

2) remove the 3 screws at 120 degrees. That will allow to retreat the focuser ring and access the stopper silver colored plate with its two screws. Move a bit the screws so that the stopper allows to move past infinite (the adjustement is just of a couple of mm, not more).

3) fix again the 2 adjusting screws to fix the stopper to its new position.

4) move the focuser tube back to its place and check (in my case I did it with a star) the focusing point to infinite so that we can put the focuser with its scale back to its correct position.

5) screw back in the 3 120 degrees screws.

6) Put the rubber band back in

 

Enjoy the lens :) .


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#4 elakrab

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Posted 23 October 2019 - 01:02 AM

Doesn't sound right, to me. I've never encountered a standard camera lens that couldn't focus at infinity... and these days, digital-camera lenses reach focus beyond infinity. If you bought it new... return it for a replacement. If you bought it used... return it for a refund.

 

It doesn't depend on the camera, it depends on the lens, the backfocus and how the stoppers are set (if there are stoppers). Not the first lens I encounter with this issue and tolerances are so low that it may change from unit to unit. Fortunately manufacturers know and if the lens is not a terrible one it should come prepared to be serviced this way. 


Edited by elakrab, 23 October 2019 - 01:02 AM.


#5 tkottary

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Posted 23 October 2019 - 01:16 AM

I have 2 of these and both of them stop right at infinity. Not a mm after that . I had to adjust spacers with 1600 and 071 to get them into focus. I will give this method a go once current projects gets done. 



#6 Traveler

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Posted 23 October 2019 - 04:42 AM

When i recieved a lens and i have to do what you did, i send it back...


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#7 calypsob

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Posted 23 October 2019 - 06:01 AM

Very interesting! I would have returned it but now you have fixed it yourself. This may be helpful for ccd and cmos users who have slight spacing issues.

#8 B 26354

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Posted 23 October 2019 - 09:06 AM

It doesn't depend on the camera, it depends on the lens, the backfocus and how the stoppers are set (if there are stoppers). Not the first lens I encounter with this issue and tolerances are so low that it may change from unit to unit. Fortunately manufacturers know and if the lens is not a terrible one it should come prepared to be serviced this way. 

Thanks. I do realize that the issue isn't camera-dependent. What I didn't realize, is that this is a manual lens. Since this is a DSLR and digital camera forum, I just assumed that the lens was a typical auto-focus lens. I always focus my AF lenses manually, whether I'm shooting terrestrial or astro... so I'm used to having lenses that do not have infinity stops.

 

Good job, fixing it! grin.gif




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