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Repair: Nikkor 85mm f/2 Ai-S

Hello, everybody! I wrote this article around a year ago and I just updated it now because I wasn’t adding any mini reviews and introductions back then so to make this article in line with our current standards, I am going to add those now. I will also do the same thing for my other articles when I have the time and I am in the mood. Enjoy my friends!

Introduction:

Today, I am going to show you the inner parts of the marvellous Nikkor 85mm f/2 Ai-S lens! I seldom shoot with the 85mm focal length because I am more into the 105mm family of lenses since it feels more natural to me for portraiture but this lens helped me warm up to the 85mm focal length for candid street portraiture because it is very compact and it is an awesome performer wide-open.

img_2435The bright maximum aperture of f/2 is very helpful for manual focusing even if you do not have a split screen installed on your camera so manual focusing is so easy!

This lens is considered by many to one of Nikon’s best 85mm lens. When it was introduced as a replacement to the very popular Nikkor-H 85mm f/1.8 lens, people snubbed this due to Nikon giving this a maximum aperture of f/2 instead of f/1.8 but it soon picked up because of it’s performance. This is the 2nd iteration of the lens, the first one came out as an Ai lens but the optics remained the same despite the coatings changed from green to purple.

(Click image to enlarge)

All of the pictures above were shot wide-open. This is an amazing lens, I remembered that my previous AF-Nikkor 85mm f/1.8D lens came with boatloads of chromatic aberration when shot wide-open so I sold it! This lens is tamer in that regard and I would even dare say that it’s even sharper, I may have gotten a lemon but I guess that you get the idea with what I am trying to say.

HAW_6064This was shot with Fujifilm Natura 1600. Look at how exquisite this lens is on film! Many people think that the f/2 maximum aperture is a step in the wrong direction for Nikon as the previous lens has an f/1.8 maximum aperture but this picture should prove them all wrong. Just look how creamy this is!

img_2434It is also very compact, it is no bigger than the usual small Nikkor primes of the same era so it can fit in your bag easily. The build quality is pretty good and very typical of ’80s Nikkors and if you took good care of this lens it will survive you and would make for a good family heirloom along with your Nikon camera. This is a must-buy given the price that this thing goes for online and I suggest that you get one because the rush for these things has begun since mirrorless shooters and Nikon photographers now have a taste for classic Nikkors!

I guess that is enough for an introduction, let’s begin with the fun part!

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:

We have discussed and outline almost everything that we need to know for the repair and maintenance of classic manual focus Nikkors so now we can begin with our first project – the Nikkor 85mm f/2 Ai-S.

IMG_1717(I like this lens so much that I own two!)

The Nikkor 85mm f/2 Ai-S is a very good lens. It is really sharp, reasonably fast and relatively compact for a wide aperture lens. In order to achieve all this, the lens has to incorporate some clever and elegant techniques in it’s construction in order to achieve the above mentioned qualities while still keeping the price cheap enough for mass production and marketing. They are not overly complicated to disassemble and maintain that is why they make good specimens for your first try into lens maintenance.

These are readily available and not uncommon in the used market because it was still in production until the mid 90’s and can even buy these from a shop brand new until the 2000s. These lenses were really popular as well so many people bought them, even people who do not really need them or know how to use one. These can come in a variety of conditions, from junk to new old stocks!

Disassembly (Focusing Assembly):

Before we start, focus your lens to infinity and set your aperture ring to f8, This will be your lens’ “rest pose” and will be a point of reference as you take it apart and reassemble it.

IMG_1721We begin by removing these 3 screws from the bayonet. Be sure to keep  your screws organised and safe so that you will not lose any. They can be difficult to buy even if you know the exact measurements. This is one of those lenses where in you should remove the bayonet mount in order to disassemble the lens properly.

IMG_1722Carefully remove the bayonet plate assembly from the rest of the lens and take extra care not to disturb the rings or misplace the little spring in the bayonet plate assembly or else your aperture ring will not work properly.

IMG_1723The aperture ring comes off pretty easily as well. Be careful not to bend it accidentally or else it will not rotate smoothly.

IMG_1725

Notice that there are 2 helicoid keys. You should mark one of them so that you will know which goes to which slot later on when you reassemble your lens. If you have mismatched them your focusing might not be as smooth as before because a helicoid key gets broken-in together with it’s slot.

IMG_1726Remove them by removing the 4 screws that secure them in place. Clean them and keep them in a safe place.

IMG_1727Be sure not to remove or damage this part. This spring is in charge of the aperture clicks. Videographers get rid of them to de-click their lens.

Remove the 3 small screws that secure the chrome ring. This ring serves as a grip as well as the lens’s helicoid stop so you cannot remove the outer helicoid unless you remove it.

IMG_1728Unscrew the outer helicoid by turning it until it gets lose. Be really careful to mark where they separate for future reference. If you forgot to mark it you will spend a lot of time guessing how to put it back.

IMG_1729Keep the outer helicoid in a safe place. Be sure not to damage the grooves!

IMG_1730The chrome ring comes off as well. Notice the notch in the ring, like what I mentioned before, it also serves as this lens’s helicoid stop.

IMG_1719Carefully rotate the front lens barrel until you see this tiny set screw.

IMG_1720Loosen the screw but be careful not to remove it. Leaving the set screw in it’s hole will prevent you from losing one as well as avoiding any damage to delicate grooves when you reassemble your lens. Loosen it just enough to remove the front lens barrel without the screw scratching the grooves of the front lens barrel.

IMG_1732With the front lens barrel gone, you can rotate the inner helicoid until it separates from the central helicoid (focusing ring). Again, be careful not to forget where they separate by placing a mark.

IMG_1733My inner helicoid separated at this point. My point of reference is the rod for the aperture should be in line with the infinity mark. Your lens might be different but it should roughly be the same as mine.

IMG_1734To properly clean the central helicoid you have to remove the focusing ring from it. Start by carefully removing the rubber grip. Be very careful not to tear it by poking a hole in it with whatever you are using to remove it.

IMG_1735The front ring is being held secure by a weak adhesive. Look for a hole in the focusing ring and drop acetone in it to soften up the adhesive.

IMG_1736 Repeat the previous step until you can loosen up the front ring with your bare hands. Be careful not to bend any of the parts pictured above or else your focusing will stiffen from the friction generated when this part and the front lens barrel are rubbing against each other.

IMG_1737Now you have access these screws. These screws are in charge of securing the focusing ring to the central helicoid. This is a very important part so be sure not to mess up the thin brass ring’s alignment by scribing marks on it before you remove any screws. This also serves as your lens’s focus adjustment when you need to get the infinity focus just right. This is a flimsy solution and to be honest, I expected more from a Nikkor.

IMG_1738Before removing the central helicoid from the focusing ring, mark it first against a reference point. In this case, the infinity mark.

IMG_1739You do not need to remove the thin brass ring after the central helicoid has been removed. The marks that you made prior to this step will only come in handy in case it was separated accidentally.

IMG_1740Going back to the inner helicoid, unscrew the front elements assembly to separate it from the inner helicoid. You may have to repeat the acetone procedure mentioned in the previous steps to soften up the adhesive that binds them to each other.

he inner helicoid also serves as the main barrel for the lens assembly in this lens. This is a clever solution to make the lens more compact as well as a way for cost-cutting.

Disassembly (Optical Block):

You can skip this part if all you need is to re-lubricate your lens. This part deals with the disassembly of the optical block. You only need to do this if you need to clean the lens elements individually in case of fungus or other debris finding it’s way into them.

The aperture cleanup procedure is also very time consuming and delicate so do this only if you really have to. There is an excellent  video on Youtube by the master “mikeno 62”. Refer to his video for how to reassemble the aperture assembly.

IMG_1741Removing the front lens assembly gives you access to the rotation plates of the aperture assembly. Before removing them, mark them so that you know where they should be aligned when you reassemble them.

Before you start, carefully remove the spring with a pair of sharp tweezers and also be very careful not to damage or misplace that tiny spring! Next, remove the 2 screws to remove the top rotation plate. You can now access the aperture blades.

IMG_1744Next, carefully remove each aperture blade and place them in a clean, soft surface to prevent damage to any of them. Bending or scratching just one of them will render your lens useless!

IMG_1742The picture above shows the rear rotation plate after the aperture blades removed. Be careful not to damage it.

IMG_1743Remember to secure both ends of the little spring with nail polish later on when you reassemble your aperture assembly. This will prevent the spring from undoing itself.

IMG_1745Removing the chromed part will give you access to the 2nd and 3rd lens element. Be careful not to drop the glass!

IMG_1754The 2nd lens element might not come off easily because this part is air tight so be careful not to damage any of the elements.

IMG_1746The ring that secures the front element required a lot of time and acetone.

IMG_1755It was held really tight and using a workman’s compass was not enough to free it so a lens spanner had to be used for extra leverage. Be careful again not to scratch your glass. The front element of this lens is badly scratched anyway but I do not want to add any new scratches to it.

IMG_1757With that pesky ring gone, you can safely remove the front element just by dropping it into your palm or use a lens sucker for extra safety.

IMG_1747Similar to the front element, the rear elements are held by a single ring.

IMG_1756Be careful not to scratch it! It may be a very tight fit for you so be patient with the lens sucker and do not poke it from the other side to force it off!

Conclusion:

IMG_1758I had lots of fun working with this lens and I hope that you did,too. This is not the simplest lens for a first project but it is simple enough for a rookie but also challenging enough for veteran.

If you have any problems or questions just leave a comment!

PS: Special Thanks to Nick Hill of Orange Elephant Photography for helping out with the grammar mistakes!

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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9 Comments (+add yours?)

  1. orangeelephantphoto
    Jan 09, 2016 @ 16:54:02

    Great article & very inspiring!

    Reply

  2. Ron V.
    Jan 12, 2016 @ 09:03:54

    This is really great stuff……………many thanks for all the valuable info 🙂

    Reply

  3. Rolf Katamann
    Jan 23, 2016 @ 13:54:24

    Great help!
    One question regarding this lens – when wide open aperture blades are not perfect round and I’ve seen this issue on three copies of this lens. I measured / compared the settings with another lens @f2 and it seems to be correct.
    Any experiences about that?

    Reply

    • richardhaw
      Jan 23, 2016 @ 14:00:07

      Yes! this is very easy to fix but it takes time. You can only fix this by cleaning the aperture blades and re-assembling them back together. this will force the aperture blades to resettle. the cause might be some dirt or rust on the pins or somebody was careless in the factory when they assembled it. y 55mm f/1.2 was like this from f/2 and I had to do this to fix it.

      Reply

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