Repair: Zoom-Nikkor 80-200mm f4 Ai-S

Hello, everybody. I have published quite a lot in the past few days because I had the time to do them. I initially plan on publishing around one post a week but seeing that more and more people are following my technical notes, I decided to publish more. I will try to write around 2-3 posts a week if I can because these take time and being a family man means that I need to spend time with the people I care as well.

Introduction:

The subject of our lens mutilation on this blog post will be the legendary professional workhorse lens of the 1980’s – the Zoom-Nikkor 80-200mm f4 Ai-S.

80200header

I got this lens for a really good price because the front elements were in a terrible state, the lens coatings have ugly bald spots and that is an indication of fungus damage. The helicoid and zoom mechanisms are still OK but felt dry and uneven.

IMG_1471

Apart from the problems mentioned above, the lens still looks great for a junk lens and considering that this thing almost costs the same as a brand new car when it first came out, I just got to have this lens.

IMG_1472

Luckily for me, the rubber still looks good as this lens’ rubber sleeve is prone to tear and warping due to it’s shape and overall length. Nikon has always had problems with their products’ rubber parts, even on the older ones where the rubber was made from a tougher type of rubber.

The lens itself was put together in a very clever way to minimise weight and size as well as to maximise the functionality of each part. My first impression when I took this thing apart was it felt like I was fixing our Betamax other Japanese consumer electronics from the 1980’s. The smell is there, the typical white lithium grease is there and even the type of plastics used in the lens feels like it came out of the 1980’s!

These “features” are all very typical of the Ai-S lenses era but with all the cleverness and thought put into it, Nikon on the other hand made a lot of cost cutting in lens production. These cost cutting decisions are very obvious, the philips screws are made from a cheaper material that corrode, some parts are held with scotch tape (started with Ai) and some of the key components were moulded from plastic. While we can argue that all this is fine because this lens survived until today and looks like it will last 50 years more, being a dedicated Nikkor user, I do expect more from a professional lens like this.

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:

The lens comes apart easily but you need to know how and where to start. More modern lenses can sometimes be a pain to dismantle. It can certainly make you feel like you are working with a puzzle and can easily frustrate you at times but once you get to know how things were put together and taken apart, you get a satisfying feeling that very few things in the world can provide.

IMG_1631

This lens was built around the zoom barrel, so you can easily remove the front and read parts and service them individually. This feature is very smart and makes servicing this lens an easy task.

With the previous statement in mind, we can divide the disassembly process into 3 parts:

  • Rear assembly
  • Front assembly
  • Main barrel

For this lens, you will not need a lot of tools, in fact all I needed were a set of screwdrivers and a lens opener to open this thing up.

Disassembly (Rear):

IMG_1606If you decide to start things from the rear (!?), you will need to remove these 5 screws first. Be careful not to strip them as these screws tend to be made of a softer alloy.

IMG_1607With the screws gone, you can safely remove the rear bayonet mount…

IMG_1608…and be sure to take notes and pictures of how things look like before you proceed.

IMG_1609To remove the aperture ring, you will have to remove these 2 M1.4 screws. These are made from a soft alloy that rust, I really hate these things to be honest.

IMG_1610With the screws gone, you can safely remove the aperture ring from the rest of the lens. Be very careful not to warp the aperture ring by accident! It does not take much pressure to warp these!

IMG_1613The chrome grip can be dismantled by removing the small (and soft) screws that hold it. This chrome grip is also responsible for holding the metal sleeve to the main barrel.

IMG_1614Store the chrome grip in somewhere safe, these can easily be misplaced.

IMG_1627With all of the above out of the way, we can now access the small set screw that secures the rest of the lens to the rear mount. They could have done this with a couple of more screws but they instead settled on this tiny set screw for cost cutting. Be careful to mark where the set screw should align with the rest of the barrel! If you get this wrong, then your lens will be off axis by a few millimetres!

Please remember not to remove the set screw from the rear mount. Simply loosen it to the point that you can turn the rear mount off without the screw coming into contact with the threads.

IMG_1628Carefully unscrew the bayonet mount from the rest of the barrel and count how many turn it took for reference.

IMG_1632You can now safely remove the inner barrel but be careful because this is actually part of the objective (optics assembly).

img_0050The iris mechanism can be separated from the rear barrel just like this after removing the screws that are holding it. Be sure to mark it’s position first before you remove it because this is one of those adjustment points that people at Nikon calibrate to a specific tolerance.

img_0052Well, the iris still looks nice so I will just let this be. I don’t want to waste my time fixing this since it’s not broken or dirty anyway.

img_0051The rear optical cell can be unscrewed just like this. Do not lose that brass shim as they are used for focus adjustment aids.

img_0054And this is how you open the front of the cell.

img_0053The rear part of the cell opens up like this. I simply used my bare hands for this. Be careful not to drop anything by the way!

These are all exposed so be very careful not to damage the blades in any way! Store these in a dust-free container. While all of these are exposed, you may want to blow some air to clean any dusts that have settled in the elements or any of the internal parts.

IMG_1629You can also safely remove the outer sleeve from the main barrel at this point.

Disassembly (Front):

You can skip the previous process if all you need to do is clean the front elements of this lens. The front assembly is easy to dismantle and only consist of a few important parts.

IMG_1611Start by removing this tiny set screw.

IMG_1612With that annoying set screw out of the way, you can now safely unscrew the front elements assembly from the rest of the front barrel.

IMG_1634The front element can be easily unscrewed from the rest of the assembly…

IMG_1636This part requires some acetone because it was held by a weak adhesive. Be careful not to scratch the black paint!

IMG_1637Just take a look at the glass, it all looks fine except for the damaged coating.

IMG_1638The inside of the front element told another story, the coating was completely eaten away on some spots by the fungus. As annoying as it is, this is pretty common for this lens in the used market for some reasons.

The soft coatings are easily scratched and can be damaged easily by simply siping it with a soft and moist tissue!

IMG_1630The glass in the main barrel is exposed so please be careful not to damage this in any way! This thing moves in and out so please do not jam this thing by accidentally.

Disassembly (Main Barrel):

The main barrel is comprised of the helicoid, zoom mechanism, the middle lens elements, focus ring, cams for zooming and other things. This is probably the most complicated part of the lens since there are so many interlocking parts. It can be intimidating for a beginner but with common sense, careful note-taking and the right tools, I can assure you that you can do this on your own.

IMG_1615First, carefully remove that wide rubber off the focusing/zoom ring. It can be hard at first due to some double sided tape or the old scotch tape used has all but disintegrated. You’re right, scotch tape! You heard it correctly…

IMG_1616remove the scotch tape and carefully remove that thin strip of brass covering the slot of the zoom key. It’s kind of flimsy but it does save weight and most importantly for Nikon, save them a lot of money!

You are also able to remove the square piece of metal. That is the key for the zoom barrel. Mark it’s position and direction by scraping one of the sides so that you know which part should face where when you reassemble the lens.
IMG_1617Before removing the lower part of the focusing ring from the main focusing barrel, do not forget to mark where they should align in relation with each other. This step should really be done before you remove the old scotch tape.
IMG_1618Once you take the lower ring off, you can now remove this retention ring by removing the screws that secure it.
IMG_1619This ring secures these thin brass shims that are used for adjusting the infinity focus of your lens. Mine focuses a little bit (2-3mm) past the infinity mark and I initially thought that my lens was not calibrated properly but other people (from the internet) also report the same issue so I guess that this is somewhat common for this lens. If this issue bothers you then you need to add or reduce the brass shims yourself. Carefully store these brass shims as you do not want to lose or bend one of them!

IMG_1622Rotate the focusing barrel until you see these screws. These screws hold the helicoid key…

IMG_1623…which you should carefully remove before doing anything to your lens.

IMG_1625Once the helicoid key is out of the way, you can now turn the front barrel loose from the main lens barrel. Be sure to remember and mark where they part as this is also the same spot that they should engage when you reassemble your lens.

IMG_1626You can now clean those old adhesive marks from the focusing barrel.

img_0039To further disassemble the main barrel, you must separate the focusing barrel. To do that you will have to remove these rollers. Be sure to use the right driver that would fit the slot properly or else you will risk ruining it because these things are glued.

This guide roller keeps the focusing barrel in place as you twist the barrel to achieve focus. It is also responsible for keeping some of the internal mechanisms in sync.

img_0040Here is another one, this guide roller keeps the inner mechanism in sync as you push and pull to zoom in or out.

img_0041And off it goes! Make sure that you noted which side of the barrel should be facing where in relation to the main barrel before you remove it!

img_0042Finally, you can also get rid of this. This roller is the shortest of them all if I remember it correctly. This one is connected to the internal mechanism which you will see later.

img_0043Here they are! I removed the nylon bushings to clean them separately. You see that dried-up thing on the thread? That’s the glue that Nikon used to secure these things.

img_0044Now, the internal mechanism that houses the internal elements groups can be removed. I would also like to remind you to note this thing’s position before you remove it so that you will know which side should face where when you reassemble it later.

img_0045What’s inside you say? Well, it’s basically a metal cylinder that houses a floating ring in it. This thing isn’t symmetrical so again, take some notes on it’s original orientation before you remove it from it’s casing.

img_0046These metal nuts are connected to the rollers so please be very aware of these later when you reassemble this. It can be a pain to get these right but you will get the hang of it soon.

img_0047Wow, just take a look at that cemented element. No wonder this thing costs so much when it came out in the ’80s! Sure, it’s not as difficult to manufacture this than say a solid piece of glass of the same shape but this is not easy to manufacture either!

img_0048Be careful where this element should be facing as you do not want to put it back facing the wrong direction! You will end up with a weird lens if you got it all wrong.

img_0049Store the lens elements in a safe place to prevent any unwanted problems.

IMG_1631Following all the steps above should result in something like this…

Conclusion:

This has been a fun lens to work with. I was initially intimidated by the lens because this is a more modern design. Lenses made in this era and later (particularly from the AF-D to current generation) tend to have complicated disassembly sequences and some parts have no way of being taken apart without permanent damage.

This lens has some of those complications here and there but I generally consider this to be an easy lens to service. All of this took me less than 1-2 hours to figure out. If I knew how things work from the start then I could even do this in less than 40 minutes.

I hope that you have enjoyed and learned a thing or two from this blog post. I chose this lens because somebody wanted to service his own Zoom-Nikkor 80-200 f/4 Ai-S lens and I thought that this would be a helpful guide for him. This lens is also considered to be an intermediate lens as far as servicing goes so if you are following my blog you are being taught little by little as time goes by as opposed to us having to work on something as complicated and confusing as an AF-D zoom lens from the start (I just hate working on AF-D lenses)!

Just like before, I would like to end this post by saying that if you find this post useful then please feel free to share or link to this blog post! I can see that my international readership is growing slowly and with your efforts, I hope that we can have a real working community where people help each other. Thank you for the motivation, 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 paypal.com account (richardHaw888@gmail.com). 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.

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24 Comments (+add yours?)

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  4. james
    Aug 05, 2016 @ 03:33:54

    Hi does anyone know what size flat head is needed to take the out the screw to get to the front element and where to get one?

    Reply

  5. james
    Aug 05, 2016 @ 03:35:53

    hi does anyone know what size screw is needed to take out the screw to get to the front element and where to get one?

    Reply

  6. Trackback: 36~72mm f/3.5 Nikon Lens Series E Disassembly and Cleaning – My Take on Photography and Diving (Underwater Photography Mostly)
  7. Trackback: Internet Nikon Repair Resources – My Take on Photography and Diving (Underwater Photography Mostly)
  8. Richard
    Dec 27, 2016 @ 18:55:26

    Hello and good evening Richard. I got nearly the same lens, just the f/4.5n.
    It is in an lovely condition. The only lack is its loose focus element which takes control over the zoom function. Other than that really wonderful. Could you have an idea how to fix this issue? Make the zoom element more tight again to get an better control over the focus?
    I would love to hear some of your conclusion and waiting to get this beautiful lens on the road again. 🙂
    Thanks in advance, marry christmas and a healthy peaceful new year for all of you.

    Richard

    Reply

    • richardhaw
      Feb 02, 2017 @ 07:49:35

      Hello, Richard!
      Sorry for the late reply, we have the same name so I ignored your comment thinking it was mine.

      You need to change the felt lining under the focusing barrel. It can be a little deep so be careful. I will write an article for this one day. Ric

      Reply

  9. Norman
    Dec 28, 2016 @ 10:23:09

    The flat head driver can be found in any cheap jewellers set. You may find it helpful to get a wetstone and “sharpen” the point a little as they are often a bit on the fat side. For the benefit who can’t help but loose the plot this does not apply to crossheads needless to say. Norman

    Reply

  10. Trackback: 80-200mm f/4.5 Zoom-Nikkor.C Disassembly and Cleaning – My Take on Photography and Diving (Underwater Photography Mostly)
  11. John
    Jan 25, 2017 @ 18:36:58

    Thanks for you great Write-Up Richard. I have one of these, but I have a slight problem, it won’t reach infinity. Is this easy to repair?

    Reply

  12. admintheresia
    Jan 25, 2017 @ 18:40:05

    Great Write Up, Richard. I have such a lens but it has a small problem. The lens is in a perfect state and smooth focus but it won’t reach infinity, somehow. Is it easy to repair?

    Reply

    • richardhaw
      Feb 02, 2017 @ 07:46:43

      Thanks! Glad that you liked it!
      I would not say that this is easy for a beginner. This lens can be frustrating if you are starting out but it’s perfectly fine once you are moderately experienced. Sorry for the late reply, Ric.

      Reply

  13. Vincent Szabo
    Mar 04, 2017 @ 00:36:57

    this is a great article Do you ever intend to take on the 80-200 f4.5 Family and a repair for the lose focus/zoom ring

    Reply

  14. Rolando Martins
    Apr 07, 2017 @ 19:31:58

    Great article Richard. I was looking for this disassemble, and comes in right time.
    Mine Nikon 80-200 doesn’t get infinity focus from 80 to 135 by a tine hair, getting a slightly blur image. At 200 focus perfectly with nice and sharp image, both on my F3 and Sony A7. In order to fix this, it is enough to remove the bottom part and them one or two of those brass shims?
    Thank you.
    Rol

    Reply

    • richardhaw
      Apr 09, 2017 @ 09:27:29

      Hello, Rolando. You can probably do 2 things:

      1: remove one of the brass shims.

      2: unscrew the rear element a bit so it is offset to the rear by a hair of a mm.

      Be careful,though as both will significantly affect the lens performance. This was probably OK on film. It is very annoying that many of the older zooms change focusing points as you zoom in and out. Ric.

      Reply

  15. Rolando Martins
    Apr 09, 2017 @ 13:06:51

    Thanks Richard. According your experience, it will be enough only dismounting the bottom part to remove the brass shim, or should I dismount too the barrel part?

    Reply

    • richardhaw
      Apr 12, 2017 @ 07:53:16

      Hello, Rolando!

      The bottom shims should do fine. I am quite worried because if you messed around with the infinity focus of one end of the lens then it will also affect the other end. Ric

      Reply

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