"Infinity Focus" and Fixing a Rokinon 135 f/2 

Just completed my surgery on my brand new Rokinon 135mm F2 to fix the focus and it worked great. I now have a perfect focus range for astrophotography.

Just tried it out on a Rokinon I had given up on and it worked like a charm! Thanks so much for this and all your other super helpful videos.

I just did this open heart surgery. I opened the lens and my heart stopped :). I used the lens on a full spectrum mod and it really does have an issue of hard stop just before the infinity focus when modding. Thanks for the tutorial!

Another short and excellent video Nico!!

Good morning. Watched your video and followed it to the letter. Fixed my lens focus problem a treat! Thanks very much!!

Such an easy solution for such FRUSTRATING problem! I bought a vintage Pentax SMC 200mm for my mod Canon M3, using a Pentax K to EOS-M adapter, I still didn't have a Bahtinov (and no experience) and I sure I was doing something wrong. It took me while to figure out that this was a focus issue, because I could focus to "infinity" in day time. Then, I replaced the cheap adapter with another one. Only after getting a Bahtinov mask I knew for sure that the problem is the focus. Asked in CN and most people suggested to add a clear lens in front of the sensor, only one person suggested to adjust the lens, which was super easy. After the adjustment I can tell for sure that adding a glass wouldn't have fixed the problem, and I love having that extra place to play with the focus. The value of a good set of mini screwdriver is underestimated in this case! Great content a always!

Thank you Nico. Did the surgery today and it works lika a charm 🤩🙏

Thanks for showing how to fix the infinity point. Appreciated!

Brilliant, that worked a treat. Many thanks for a clear and concise set of instructions 👍

Great tutorial, Nico! Worked perfectly for me.

Thanks for sharing this Nico. I also had the problem with this lens and my Sony A7S and ended up sending it to an official service to fix it. Thanks again!

Thanks, Nico. I have the same lens but have not had an infinity focus issue yet. Great video in case I need to fix.

Week 24 of appreciating Five Minute Fridays

Good morning Nico. I followed your instructions to the letter and problem is resolved 💯% Many thanks and keep well. Warm regards, Mupanga Lusaka, Zambia

No more problem after removing the hard stop. Very easy Thank you so much. Dominique

Very informative video as always Nico! I actually went the opposite route and adjusted the sensor on my Rebel T3 to its maximum forward adjustment, which overcame the focus issue. That route was NOT easy and takes a lot of patience due to the complexity and inner workings of DSLR's. Unfortunately, that camera decided recently to give up the ghost. I think this time around I'll go this route when the replacement modified camera arrives. The 135 Rokinon has been a staple for my Astro images but excels in the daytime as well!

Thank you very very much Nico!. I've a Samyang 8mm f3.5 lens that has some infinity focus problems. I was even trying to sand the mount piece to reduce the distance for that lens to achieve a better focus, but, in the end, after watching this video, fount that the 8mm lens has the same screws for adjusting! This will make that lens interesting to me again. Thanks!

Many thanks! Great simple tutorial that worked.

Very informative and helpful. Thank You!

A great tutorial. I bought the Samyang 135mm lens this last summer and tried it out quite recently with my modified Canon 600D and a Bahtinov mask. I reached perfect focus at the hard stop which was fortunate because I couldn’t go beyond that to go slightly out of focus, if that makes sense. Then I put an Optolong L-Pro clip in filter into the camera. I found that with the filter I could rotate into and out of focus perfectly at F2.8 which seems to be the sweet spot for this lens. This may help others with a similar problem without having to ‘surgically’ adjust the lens.

I love this Tair 300 f4.5! I have it and made a nice shot of orion using my 7D. But I didn't use stacking, it is only single exposure.

Just the video I was looking for. My 135mm f/2 can't focus properly and I will surely give your solution a go.

Thanks. Great video. I had just received my Rokinon 135 mm yesterday and noticed there was zero play beyond the infinity focus. I thought that was very strange and worrisome until I came upon your video. I just did this mod using your instructions. Just a couple of observations from the experience I had. Some things that weren't said or immediately obvious although they were certainly shown in the video. 1) Even with the right screw driver some of the first three screws were overtightened at the factory and tough to get out. I really had to press hard to prevent the PH00 from climbing out of the grooves and damaging the screws 2) As shown in the video its important to make sure you get the rubber grip pushed all the way to the end of the lens in order to get to the hard stop 3) Also as shown in the video, going around the grip in a circular fashion with fingers under the trailing edge is the best way to get it to slide down otherwise it can be tough to move. 4) When replacing the three screws at the end I was having a hard time lining up the screw holes but playing the video back at half speed was helpful there. Thanks again. I probably wouldn't have done this without the video

Awesome video because I bought an off brand oshiro 135mm f2.8 lens and the infinity has been giving me a problem for lack of better terms. Clears skies in the NORTHEAST 🇺🇸 TONIGHT.

Cool, I've got that 300mm lens, I have the full Zenit photosniper kit it came in including the gun stock for it which is why the focuser is part way down the lens body :)

Great Tutorial Nico!!

Thank you for that tutorial! I am not sure if it's a good idea but instead of removing the stop entirely, I moved it one screw to the right. This way I can go slightly past infinity, and still have a hard stop for safety.

I just had a friend 3d print me a bahtinov mask for the lens hood for the Rokinon 135 and it works perfect.

Tips: gently heat up the focuser rubber with a small heat gun (emphasis on gently) and slide it down instead than up. Completely remove the stop. It is actually a "pre-stop". There is another internal stop once it is removed.

Fantastic, clear and precise. As Usual! DG New Forest U.K.

It worked for me! Thanks!

Excellent tip! Now i just need to buy this lens :)

You're a life saver Nico! I actually bought a used lens myself a few days ago at an incredibly cheap price (less than half if new) for a like new lens - just that it has this issue. I'm having a hard time noticing bad focus myself (bad eyes probably lol), but my bahtinov mask says it doesn't quite reach focus. Just to clarify, before removing the screws I'm suppose to put it as far to infinity as it goes, as in, reach the stop? But yea, seems pretty easy and I'm gonna have a hell of a good time with it after it's fixed

Thanks for this. I could never understand why you couldn't just turn the lens to infinity and the stars would be in focus. Now I know :-)

Thanks Nico, great video as always, and an interesting tip :-) Do you have any plans to do a 5min Friday on backfocus, as you mentioned in this video? Especially for dedicated astro camera (eg ZWO ASI 533), reducers / telescope combos (eg. William Optics 6A III) ... it's so challenging to understand which set of measurements etc. to utilise from each device.....

Awesome 👏 this worked for me Thank you 🙏 🔭🤩📸

Interesting, my solution to this exact issue was opening up the camera and shifting the sensor forward.

Hmmm...wonder if I will have this problem when I finally go to use my Samyang 135mm with my ASI294MC Pro. I know what to do now, if I do...great video, Nico!

thumbs up for the TAIR-3 :D

the hardest part is the rubber. Thanks for the guide :)

hi Nico, question about the stopper that you removed. Is there any risk of over focusing and damaging the lens if you dont put it back in? eg. if you twist the focus ring past its intended infinity point and collide some of the internal optics? or is this not an issue? cheers

The missing sensor glass / ir Pass filters of astromodified cameras prolong the light path to the point of convergence by 1/3 of their thickness as a rule of thumb. I had to learn it the hard way on my Sony a7rII. I still have some lenses with which I cannot reach infinity focus fully open. This is really helpful advice and luckily an easy procedure on one of the cooky cutter lenses for ap :)

Thanks for the info.... my Samyang 135mm F2 is now operating as it should have to begin with.

Hey Nico ! Thanks for the video!! My Rokinon lens stops at the backwards " L ". Nowhere near the infinity symbol. I will order the magnetic pad, screw driver set and fix my lens.

After fixing my 135mm F2 following this method, I tried it on my Samyang 24mm F1.4. However the 24mm has a different construction so it requires starting from the back end and removing the mount ring and aperture ring. It's a more complicated process, but still achievable using the same tools.

Especially complex lens designs with ED, UD glass elements change shift in focal length / focus shift due to temperature changes.

This is super helpful! Are you aware of any difference in the process on the cine (other than the rubber not being there? Not sure which screws to pull

Спасибо за ролик!!))) Ваш преданный подписчик)!

Thank you for the tutorial! So removing the silver hard stop piece is the solution. That's a much better option than moving the camera sensor

I wonder if this could be useful for my canon 50mm nifty fifty, with my astro modified 6D I'm just slightly out of focus at the hard stop.

Nice move Doctor. :)

Thank you. My Samyang arrived this week and I was anxious about this very issue. My focus ring does not rotate all the way to the infinity symbol...but I tested it out with my DSLR on a tree that I know to be over a mile away. Looks like I can just go slightly past true infinity focus....on my DSLR. I'm going to be using it with my ASI183MC Pro and the last of my adapters arrives today. Once I have that, I will test the focus out using FireCapture and follow your tutorial if I notice I can't get there. We're forecasted for 3 clear, moonless nights in a row, starting tomorrow night. Does this inability to reach infinity focus get better or worse as temperature decreases? Intuitively, I would think that it's worse at warm temps but maybe I'm backwards on my thinking.

Very Helpful, Thank you very much, now my question would be, would tfor my APSC and my full frame camera?

Great Video Nico! you should be a teacher

Did you do or plan to do a project with TAIR 3? I have the same, and it looks to me that it is not able to reach infinity after it gets cold. Do you know if there is a way to modify it to go a bit over infinity?

Awesome info, Nico! One question, are you saying you could adjust the aperture to fix this.? Stop down and achieve infinity? That won't help my situation, however., as I have this problem with a fixed aperture lens. :( I just discovered my 14 mm Rokinon doesn't reach infinity on my Pentax. Very disappointed about this, especially on the wider lens... Why not make the travel go well past infinity? What are they trying to avoid by making it such a narrow range of movement? Thanks Nico! I thought I was going to have to return the lens. I'm not sure I'm ready to perform surgery on my own, but will be talking to my local repair shop. Clear skies... N

Hi Nico, thank you for another informative video. For clarification, in step 3, you took off the small silver piece. Do you replace that afterwards or does that prevent you from making the adjustment? Thanks again. Clear skies! Narrie (The Nar Side).

Do you have to put the silver piece that controls hard stop back after testing or not?

Hey, Nico! I have the Samyang 135mm f/2.0 and I am having the issue you've mentioned in this video. The lens won't focus all the way to infinity. I peeled back the rubber grip of the focus ring, however, the screws that I need to unscrew are extremely tight. I don't want to risk breaking the lens (from using force to undo the screws). Is this issue specific to the 135mm or does it vary? I am wondering whether to send the lens back in exchange for a new one but I don't want to do that if the issue will persist. Any thoughts?

That works perfectly for my 135mm,but I have the Samyang 50mm,where there is not a ring that I can pull after unscrewing those 3 small screws. Anybody any idea or link to a description that helps me with my 50mm?

Would you recommend the same approach with the Rokinon 14mm f/2.8? Thanks!!

i have a samyang 50mm f1.4 and a 14mm f2.8 Series II that don't focus to infinity on my astro-modded 6D....they unfortunately don't have this same 'stopping mechanism' so I guess I'll have to sell them EDIT: fixed the 50mm f/1.4 Samyang's focus, it's a bit more involved but definitely doable. had to take the back mount ring off, the aperture ring and ball bearing out, and then completely slide the focus plastic ring off after loosening the same screws featured in this video. then you remove the white sliders, rotate the focus around once to get past infinity, then re-assemble.

Really wanted to try this because even after going for repair couple of months it came back with same issue....but I had to quit before really getting started. 2 out of 3 screws weren't moving...hope I didn't strip them entirely. Any hints to get them loose?

Good info. But what is interesting (maybe my lens is older or newer) but my Rokinon f/2 135mm has a different labeling setup. Meaning, as seen at this video (3:30) your label is L then the infinity symbol and then m. On my lens... its m infinity symbol and then L. Does this make any difference in regards to doing this tweak?

Hi Nico can you recommend some laptop software to control a dslr settings so I don't have to touch the camera once guiding?

Always yours.

My Rokinon has infinity focus about 3mm to the right of the. indicator on the lens.

I have a question About focus. When im shooting The stars, i bump Up all my settings to max - 30sec exposure, F1.8 and iso 1600 (thats max on my camera) I focus using live view at that settings. Will my focus change, When i change my f value or aby setting? Thank you for reply😊

Hi Nico, I did the fix this morning but when I reach the infinit icon i lost the focus on the ground, maybe I did it wrong?

I tried this mod but one of the three screws was too tight and I was unable to get it out. Lens was returned.

you don't place back the hard stop screws?

You're joking 😯 I have had this lens for 3 weeks, battled with the infinity issue continuously. Thought it was faulty, so have just returned it 😒

I just bought this lens and found the same problem. As this is a known issue, how can it pass muster at the factory? I tried focusing on some distant mountains and could not get that last ounce of clarity as the infinity symbol would not his the last mark. I'm going to mod my "Brand New Lens". Makes no sense.

Heres a question. Do you just remove the little mmetal clip all together?

Niko, when I tried these steps, it just moves by a couple of mm off Infinity mark. But continues to lock after that. Is that all the extra turn we get?

Question 🙋🏻‍♂️ once the hard stop is removed can the lens be damaged by someone turning it way past infinity? I wouldn’t but a child might or a drop incident.

So, my lens doesn't go that far to the left of infinity. Am I just position the screw position on the left side of the small slot instead of the right now?

I know this video is older now. I just ordered this lens, and was wondering what the purpose of infinity focus was for astrophotography (I'm new to AP)? What are the use cases for it? Thanks all! Clear skies!

I bought a Rokinon 135mm F2.2 ED UMC thinking it was a 135mm F2 lens. I want to use mine for astrophotography. Is there much difference? Also, I cannot select F2.2. Stops @ F4. Nor can I select Infinity. Is this normal? Thanks for your videos. Much appreciated. Mike

Can you clean the Samyang 135mm f2 inside?

I wonder if this works with my 8mm fisheye..

What would happen if we go to far beyond Infinity focus without hard stop ?🙈

Это Таир-300фс в начале?)

thanks, i was able to do this with ease. Thanks...was finally able to focus in landscape test. Now for some clear skies...

I'm having big dramas with my recently astro modded Sony A7C when using wide lenses like the 14 and 24mm GM. They do no longer reach infinity focus at all when wide open or anywhere near wide open. Kind of looks acceptable past f4, but that defeats the purpose of an f1.4-f1.8 lens hey. 135mm GM at f1.8 works fine. Very disappointing experience thus far.

Hi Nico. Don’t suppose you actually know the screw size. Tried with screwdriver I have with no joy. Need to get a decent set

Hi

there’s no way that this manual focus lens will consistently serve you with accurate focus, the way an AF-lens on a mirrorless camera using contrast based autofocus will. i have great results, as an example, uaing a Fuji GFX 50R with the 32-64 mm GF lens at f4, also for astro.

Time to get rid of the covid hair.

Thank you!! I was nervous about operating on my lens, but after watching a few times I gave it a go, and all went smoothly!