Repair: Nikkor 135mm f/2.8 (K/Ai)

Hello, dear readers! How are you this weekend? The weather here in Tokyo is beginning to be unbearably hot as mid summer approaches, there are afternoons where the mercury would even reach 38! Please stay hydrated by drinking plenty of water because I do care for your well-being. I do not wish to read about a photographer who collapsed because of heat stroke, that would definitely spoil my mood. Do take care.


Today, we are going to talk about the Nikkor 135mm f/2.8K lens! For those of you who have been following my blog for some time you may have remembered that I made a tear-down guide of the Nikkor-Q 135mm f/2.8 lens earlier this year – this lens is it’s successor!

IMG_0324This lens looks great on modern DSLRs like this D750. It’s image quality can still keep up with the best of Nikon’s (or Sony’s) sensor technology!
The Nikkor-Q 135mm f/2.8 is a lovely lens and it’s rendering has plenty of character because it can make the background melt into a wash of colours while leaving the focused area pin sharp when shot wide-open. It seems to be a very difficult lens to succeed but good news! This lens is just as sharp and performs even better! Nikon has revised the optical formula by adding another element to it and added improved coatings. Nikon has also changed the chassis of the lens to make it more compact and lighter as compared to the previous lens.

(Click to enlarge)

I am not going to make a detailed review of this lens because that is not what this blog is about and I am very sure that other people can make better lens reviews than me but from the pictures above of the cat and the monk, you can see that this lens is a performer from minimum to medium distances wide-open. The pictures are delicate but not unsharp and the background just melts into nothing on the cat picture.

IMG_0325Here is the lens when compared to the Nikkor 105mm f/2.5 Ai-S. You can see that it is not a lot bigger than the smaller lens. It is actually impressive because even with the reduction in size and weight, Nikon actually managed to retain the retractable hood feature which is very useful when you need to shade the front element from stray light or protect it from dust or other things.

IMG_1171.JPGCompared to the older lens you get around a 40% reduction in size, if that looks impressive in numbers wait till you actually have both lenses in your hands! The Nikkor-Q 135mm f/2.8 is built like it could withstand a nuclear war but the subject of our post today is built tough as well and will give you many decades more of service provided that you keep it clean and well-maintained. This is something that the electronic lenses of today will never achieve.

Having mentioned all that, let us begin opening this lens up so that we can appreciate just how well this lens was engineered!

Before We Begin:

If this is the first attempt at opening a lens then I suggest that you read my previous posts regarding screws & driversgrease and other things. Also read regarding the tools that you will need in order to fix your Nikkors.

I highly suggest that you read these primers before you begin (for beginners):

Reading these primers should lessen the chance of ruining your lens if you are a beginner. Also before opening up any lens, always look for other people who have done so in Youtube and the internet. Information is scarce, vague and scattered (that is why I started this) but you can still find some information if you search carefully.

I highly recommend that you also read my working with helicoids post because this is very important and getting it wrong can ruin your day. If I can force you to read this, I would. It is that important!

For more advanced topics, you can read my fungus removal post as a start. This post has a lot of useful information here and there and it will be beneficial for you to read this.

About Me:

I am a photographer based in Tokyo who scours the junk section of the camera shops here on a regular basis. I started this hobby of fixing old lenses and cameras because I kept on getting scammed before when I purchase online. This turned out to be a blessing because I now buy junk lenses for a fraction of the price and then fix them to add to my growing now collection. This allowed me to buy gear that were otherwise off-limits to me if I were to get them in better condition.

I was a scale modeller before who built models for other collectors for a very longtime, got an education as a dental prosthodontist (but didn’t pursue dentistry) and growing up in a watch repair shop gave me the useful skills that would help me in this craft. Fixing my car also contributed some know-how.

Having mentioned the above, I will tell you now that I am not a professional repairman! So please take what I do with a grain of salt and I will never be held responsible for anything wrong that will happen to you and your project. I hope that the pros would guide and teach us but nobody is writing anything.

As my collection of repair notes grew, I get requests from people with similar interests and from professionals who just needed some notes just in case. Now, I am sharing my library with you for your entertainment and reference. I hope that you find my work useful.

Disassembly: (Foreword)

This lens is actually the K (New-Nikkor) version but the lens is so similar to the Ai and Ai-S versions so you can somewhat use this guide for those versions of this lens as long as you take into account the small changes Nikon has made to improve the engineering of this lens line and cost cutting.

IMG_0254Make sure that the lens is focused all the way out to infinity as you are work with any lens. This will give you a reference position as you remove parts or reassemble your lens. Always take plenty of notes while the lens is at this position. This is very important and it is just one of those things that you will learn as you go about dismantling lenses.

This lens is not difficult to work with if you have already worked on a couple of lenses but I would like to stress that you should be careful as lenses of this era and vintage can be a bit delicate because of corrosion and the manufacturing methods and standards of the time. I will tell you which part you should be careful with so don’t worry.

Disassembly (Focusing Unit):

We will begin by removing the objective (optical assembly) from the focusing unit / barrel. As usual with Nikkors of this era and class, we start by working on the lens from the front.

IMG_0267Begin by extending the hood.

IMG_0268Rotate the hood until the hole on the hood lines up with the small set screw. Unscrew that set screw so you can remove the front ring.

IMG_0292Now, retract the hood again and remove the front ring. The front ring might be secured by adhesives so try placing a drop of solvent like acetone into the hole for the set screw and let that sit for a couple of minutes. Look at the picture above, the front ring has a hole in it and that is where the set screw was secured.

Get a rubber pad that is big enough to cover the front ring and use it to remove the front ring by using friction. You may want to put your elbow into it because these things can be tough to remove at times.

IMG_0293You can now remove the hood from the front barrel. Be careful not to damage the felt on the inner surface of the hood! You can remove the objective after this step but I chose to leave it there as I wanted to see how things were connected inside before I remove it.

IMG_0270Now, on to the back of the lens. Remove the 5 screws on the bayonet mount. These screws are secured with generous amounts of Loctite so be sure that you put a drop of acetone into each screw and let it work for half an hour before you attempt removing any of these. You can also use a soldering iron to head these up to soften whatever was used on these. Also be sure to use the proper screwdrivers for the task – it should be JIS.

IMG_0271Carefully remove the bayonet from the rest of the lens. You may be tempted to remove the aperture ring at this point but just leave it there for awhile…

IMG_0272The aperture ring is being held by these 2 screws so you have to removes these to get that aperture ring out. This is a non-Ai’d aperture ring so I had to convert it to Ai. If you want to know how I go about converting my aperture ring to Ai, head over to my Ai conversion post.

IMG_0273With those screws gone, you can now safely remove the aperture ring.

IMG_0274OK, so this is how it looks like inside. We would never have seen this picture if we removed the objective earlier.

IMG_0275I should have removed the rubber grip earlier but whatever. Simply run a toothpick or any round tipped tool along the whole circumference of the rubber grip to loosen the glue used to hold it to the focusing ring. Look at the picture and you can see the residue left by the decades-old glue. Remove the grip carefully because you do not want to damage this.

IMG_0294The objective is being held by 3 small screws near the edge of the barrel. Remove these and you can safely pull the objective out from the barrel.

IMG_0295As you can see from the picture a few steps earlier, the rear part of this lens is packed and cramped. Now that the objective is gone, you can now easily remove the smaller parts and not having to worry about damaging anything in the process.

IMG_0296To completely dismantle the focusing ring to it’s bare parts have to remove the scale first by removing the 3 set screws that hold it in place. Be sure not to lose any of these!

IMG_0297This grip should be removed as well so unscrew these 3 screws.

IMG_0298The grip might be glued in your lens, mine wasn’t so it was easy to get this undone. If your grip is glued in place then you should apply some solvents or alcohol first and let that work before you remove this.

IMG_0299This sleeve has to go as well. Again, you have to do the alcohol or solvent routine on this.

IMG_0300Now that nothing is in the way, you can now remove the scale from the lens. Be sure not to damage this as this part is thin and easily bent.

IMG_0301The focusing ring itself is being secured by these screws…

IMG_0302Remove the screws and the focusing ring can be easily pulled away from the lens barrel.

IMG_0303To remove the front barrel from rest of the focusing unit, simply remove these screws that secure it to the helicoids.

IMG_0304The front barrel should come off easily…

IMG_0305Before we start separating the helicoids we should scour some marks first so that we know how and where the helicoids should mate later on when we reassemble the lens. If you did not mark or note the helicoids’ positions and tolerances then I assure you that your going to have a very stressful time guessing their position in relation to the infinity mark.

I made a couple of marks on the helicoids – one for the infinity position, another to mark the maximum compression of the helicoids. This is my personal lens so I have the liberty to mark it however I want but if this lens belongs to somebody else then I would mark this lightly. They say that a skilled repairman leaves no marks, that’s true! I am not as skilled.

IMG_0306Once you are satisfied with your notes and markings, simply unscrew those 2 screws in the previous picture so that you can remove the helicoid key. Be careful with the screws since these are usually epoxied into place. If you are lucky, these will be secured by Loctite but if you are working on a K-era lens then it will most likely be epoxied. You can tell if it is done with epoxy if you see an epoxy bead or smell the parts for that familiar peanut butter-like smell of epoxy.

Some people will touch this with the tip a soldering iron and let the heat soften up what is there, I simply use solvents to dissolve whatever was used. There will even be times when the screws used on the helicoid key will snap due to age or left over glue so be careful! If that happens then you have no choice but to bring out the screw extractor or drill out the screw (or what’s left of it) and re-tap the screw hole to clean up whatever material is left.

IMG_0307Separate the outer helicoid from the centre helicoid and make sure that you mark or note where they separated. I marked where they separated with a small arrow pointing to the infinity mark.

IMG_0308Now, separate the inner helicoid from the central helicoid and mark where they separated. Look at the picture above to see how I went about marking these positions.

Disassembly (Objective):

IMG_0309Simply remove the front front elements group by unscrewing it from the objective.

IMG_0312Begin by removing the last element on the front elements assembly by unscrewing it.

IMG_0313Now, on to the front! Remove the retention ring with a lens spanner and be careful not to scratch the front element!

IMG_0314Once the front element is gone, you can now access the second element.

IMG_0321The next lens element is being secured by a retention ring. Use a lens spanner to carefully remove the ring without damaging the glass.

IMG_0322Once the retention ring is gone, you can carefully extract this big chunk of glass from the barrel. The tolerances of these parts are usually very fine so it may be a tight fit for this so just take your time.

IMG_0310The rear elements group also comes off easily by simply unscrewing it.

IMG_0311The rear elements can be difficult to access without the proper tools. To find out how I got mine to separate, read this blog post about making your own DIY lens spanner.

IMG_0319This ring is usually glued in place so place a drop of alcohol to soften up whatever is there. Mine came off after a few seconds of saturating it with alcohol.

IMG_0320Now that the retention ring is gone, you can now remove the rear element from it’s barrel. Be careful and note which side of the element should be facing forward or else you will end up with an “art lens”.

Infinity Focusing:

Before you put everything back together, assemble your lens until you end up with what I have in the picture below. You want to assemble the lens so that it can be mounted on any Nikon camera but still having all the necessary adjustment points accessible for you to fix the infinity focusing of this lens.

IMG_0323You can adjust your infinity focus by loosening these screws a bit. Be careful not to loosen these to much because you may accidentally drop whatever is holding this brass stop. Just loosen them enough so that you can slide this brass stop left and right.

For this step, I like using Nikon’s modern DSLR’s because they have very accurate focusing indicators. Simply focus your lens on something distant around 2 or more kilometres away and when the focusing indicator circle lights up in the viewfinder then that is where your infinity focus should be. Make sure that you do not move your lens accidentally and push this alignment off. Move this brass stop to the left until it cannot go any further, tighten the 2 screws and check again if your focus is spot on when you focus on a far away object. If it is still OK then you got your infinity focusing right – congratulations!

Next, finish it off by adjusting the scales of the focusing ring until the infinity mark is dead centre on the focusing dot and the white line.


I got this lens from the junk corner of my favourite camera shop here in Tokyo. It was sold to me for a reasonable price so I took it, I was looking for one anyway. While the lens itself is OK, the helicoids were rough and the exterior has some scratches here and there so that is probably the reason why this was sold as junk. Well, one man’s junk is another man’s treasure!

This should be an easy lens for somebody with a little bit of experience opening up lenses. I hope that you learned something from this so you can start fixing your lens, if not I hope that you enjoyed seeing how this lens was put together and appreciate it’s engineering. If you have not “liked” our companion Facebook page yet, please click on this link and press the “like” button to get updates on new posts, interact with other people who have similar problems and interests as well as showing off whatever gear you found in the junk shop. I would like to thank you for the continuos support and until next time, Ric.

Help Support this Blog:

Maintaining this blog requires money to operate. If you think that this site has helped you or you want to show your support by helping with the upkeep of this site, you can simple make a small donation to my account ( Money is not my prime motivation for this blog and I believe that I have enough to run this but you can help me make this site (and the companion facebook page) grow.

Helping support this site will ensure that this will be kept going as long as I have the time and energy for this. I would appreciate it if you just leave out your name or details like your country and other information so that the donations will totally be anonymous it is at all possible. This is a labor of love and I intend to keep it that way for as long as I can. Ric.


16 Comments (+add yours?)

  1. Ron V.
    Jul 10, 2016 @ 06:17:01

    Perfect timing with this post Ric.
    I have to replace the front element in one of these lenses next week, first time I’ll be stripping down a K version.
    Thanks for sharing the procedure 🙂


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  3. Simon
    Nov 28, 2016 @ 18:40:50

    Wow! Well structured guide with lots of good advice. A truly helpful article… With this tutorial I fee confident to bid on an U.G.L.Y 2.8-135 Nikkor that came up on eBay… wish me luck.


    • richardhaw
      Nov 30, 2016 @ 09:03:11

      Hello, Simon! Be sure that you have the right tools first! The most important thing to master and learn is how to work with the bayonet screws. Make sure you saturate it with MEK for a couple of hours if it’s stuck. Ric.


  4. Charlie
    Dec 21, 2016 @ 09:33:27

    Be careful,Simon, as all those screws have JIS, not phillips heads. They look nearly the same, yet wrong screwdiver can easily strip the screw. Instead of acetone, you can heat the screw with fine tip soldering iron.

    Moody tools makes reasonably good JIS drivers


    • richardhaw
      Dec 21, 2016 @ 23:44:16

      Hi, Charlie! I have a small butane torch for this but I rarely use this nor the acetone trick anymore since I got myself a long shafted VESSEL driver. Ric.


  5. Forood
    Jan 29, 2017 @ 18:30:51

    No body could depart a Nikkor 2.8/135 and show them online better than you.
    I just have one question, where is the small screw bellow the shade that I have to remove to accomplish the very first stage?


    • richardhaw
      Jan 30, 2017 @ 02:20:35

      Thanks for your appreciation! As for the screw, unfortunately, you will have to look for it. All you need to do is rotate the hood until see the screw hole. It is going to take some time but my technique is to line up the hole just 2-3mm below and above where the seam of the front ring is and just rotate the hood until I see something. Ric.


  6. luigi
    Mar 11, 2017 @ 17:28:59

    but how to open the aperture to clean the leaf!!!!!!!!!!!!!!


    • richardhaw
      Mar 12, 2017 @ 02:43:47

      Hello, Luigi!
      Mine was OK so I didn’t have the need to open it. I forgot how it looked like exactly but you should begin my removing the 3 screws on the iris casing and also the screw on the brass rotation ring. Be careful and read all of my articles so you are familiar with how Nikkor irises look like. Ric


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  10. DANEL
    Mar 21, 2018 @ 16:40:04

    i have a nikon 50-300mm f/4.5 non ai with the zoom ring blocked, can you help me?


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