Repair: Zoom-Nikkor 35-70mm f/3.5 Ai

Hello, everybody! I was watching some videos of my favorite musicians when I was young and I was shocked to see them categorized as “oldies”. Some of them still sound great while a couple seemed “dated”. I consider them to be quite decent in their time but now they’re totally irrelevant, just a blip in the music scene. This is not to say that they’re bad if you put their music in the proper context, they did entertain us at a time when a lot of musicians simply made bad music. Today, I will show you something that used to be quite good at a time when many of its contemporaries simply couldn’t make the cut but it’s dated today, something that’s best left to the lens aficionado to appreciate. Read this article to know what this lens is.


The Zoom-Nikkor 35-70mm f/3.5 Ai was sold from 1977 to 1981. It’s one of Nikon’s original “standard-zooms”, it was revolutionary in a way since it covers some of the most important focal lengths used for photojournalism and events or travel photography. That allowed this to replace 2 or 3 lenses, a big convenience at a time when carrying several prime lenses was the norm. Its maximum aperture speed of f/3.5 is respectable but not as fast as most primes lenses, that’s a price many people were prepared to sacrifice for convenience. I suspect that it was made for use by professionals because it has a constant-aperture and other features that many of use will consider to be premium such as the amazing build quality and its well-corrected distortion profile.

Unlike many zooms of its time this one came with separate zoom and focusing rings. That means it’s better for shooting with a tripod since zoom-creep won’t be a problem. You could make precise turns with it, too. All this suggests that it was originally intended for shooting with a tripod instead of action photography. I was merely making an assumption with that statement.

It has a 10-elements-in-9-groups design which I think is quite elegant. Image quality varies depending on who you talk to but it’s generally considered to be quite good for its time. It appears to be quite decent if you stop it down to f/8 but can be hit-or-miss when shot with wider apertures. This helped its reputation because several zooms of its time performed poorly on top of having terrible distortion. It’s not as impressive today specially when you shoot it with a modern high-resolution camera. Closest focusing distance is a pathetic 1m which is a shame since it would have been a lot more useful if it could focus closer with the wide-end, limiting its use.

The front flares-out so you’ll need 72mm filters for it, a huge size back-in-the-day. The build quality is superb, I like how it feels when held, it’s dense and the balance is quite good. This was certainly made to endure use in the field.

It works great with my Nikkormat FTn. It’s front-heavy but that’s the price you’ll have to pay for convenience. That was especially true when this lens came out because there weren’t many alternatives around. We have a lot of alternatives to choose from today which are smaller, lighter and better in terms of image quality.

It doesn’t have the colorful engravings that we’re used to seeing in many older Zoom-Nikkors, this one is more conservative in terms of styling. You do get minimal markings to help you with infrared photography but that is all, no depth-of-field scale at all.

Learning how your lens performs is key to maximizing its use. You will learn how to utilize its strengths and avoid its weaknesses. This knowledge helps in determining which lens to bring on a job. I shot these photos from f/3.5f/5.6 and f/8, these are the most common apertures that people would want to use it and we’ll see the most changes happen with these values. The photos were shot with my Nikon Df.

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Distortion is quite well-controlled for a zoom of this age. The amount is moderate but the profile can be a bit complex on the long-end but it’s not something that you should worry about.

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Flare and ghosts look terrible with the latter being the uglier of the two. Flaring looks acceptable to me despite its tendency to cover the frame in worst cases but the blobs look terrible.

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Vignetting looks terrible wide-open at the wide-end but it improves considerably by f/5.6 and is gone by f/8. It’s a lot better at the long-end which suggests that this lens performs better at 70mm.

Flare can veil the whole frame and cause it to lose some contrast. You’ll get blobs in your frame even if you’re not positioning the sun within it. This is something that you should be aware of, despite that you could use it to your advantage since it will add another layer of “interesting” effect to your photo.

This is how bad ghosts and flaring looks like in real-world scenarios when it’s stopped-down. This is ugly, the blobs are distracting and certainly unwelcome in any case.

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The character of the bokeh is quite bad, you’ll get rough-looking artifacts which can be difficult to avoid if you are shooting with foliage and twigs in the background. You must be careful with it in order to avoid this look. I don’t think this will be a big problem so long as you’re aware of this issue and stop the iris down a bit and just avoid any high-frequency details in your background.

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Here are more photos showing background and foreground blur characteristics to help give you more idea as to how it really performs in this aspect.

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Chromatic aberration can be seen wide-open at overblown areas. It’s more prominent at the long-end but this doesn’t mean that it’s any better at the wide-end. It improves by f/5.6 and you’ll only see traces of it at f/8. You will notice that spherical aberration is the worse of the two but it doesn’t look as ugly so I’ll tolerate it.

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It’s actually quite decent wide-open when focused at further distances but I can’t say the same when it’s shot from close to moderate distances. A big factor leading to the decline in image quality is spherical aberration, I find it too-high as to actually affect sharpness. Shooting with it in the shade helps somewhat, too. Resolution is lacking wide-open but it’s adequate when shooting small prints. The corners don’t look good at all but I do not find them unusable. Nobody zooms-into the corners and expect them to look great except in reviews. Stop the iris down to f/5.6 and the center looks better. The periphery looks better as well apart from the extremities. Its resolution improves quite a bit and that helps render sharper photos. It’s actually not bad at f/8, it looks quite nice at the center and the corners begin to look a lot better, too. The corners still lag behind the center, they’re about 1-2 stops behind so stopping it down to f/11 will help bring them up to acceptable standards. This is not a bad lens at all but it’s certainly showing its age.

Spherical aberration is quite high wide-open at closer distances. I don’t mind it to be honest but I certainly do not like chromatic aberration in any way. This is barely-acceptable for me which means it’s mediocre to bad. I won’t put this against this lens since it was made at a time when designing zooms was difficult.

This is how close it could focus. Resolution and sharpness is lacking wide-open which makes the photo look a bit “dreamy”. One thing that’s obvious here is the outlines of the discs, stopping the iris down a bit should help make it look a bit cleaner.

It’s great as a travel and photojournalism lens because it covers some of the more-important ranges for them. This lens was made for convenience over performance if you ask me.

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It certainly shows its age when shot with modern digital cameras. People will either like this or hate it but it’s certainly something that is worth documenting because it’s an important lens in terms of history. Remember that this lens was in pretty bad shape so my results shouldn’t be indicative of what it could do.

Let’s now check some film photos. Film has a unique look that is hard to simulate with a digital camera thanks to grain. It reacts differently to light, this means that it could mask a lens’ flaws or amplify them. Since it was designed to be used with film, it’s best that we judge this using its intended medium. Some of these were taken with the iris stopped-down unless there’s not enough light.

It shows acceptable quality when shot with film so its lack of sharpness and resolution won’t be obvious since grain helps mask it.

Despite having terrible flare and ghost resistance even with film it looks a lot more acceptable in my opinion. Shooting with film means embracing imperfections at times.

Spherical aberration can be observed here but film’s organic look won’t make it obvious unless you look at it carefully.

The distortion amount isn’t high even for an old zoom, relatively speaking, of course. I find this impressive, it’s one of the things that helps make this lens usable.

This is how bad the distortion looks like at the wide-end on a real-world scenario. Avoid positioning your lines parallel to the edges of the frame so you won’t notice it much.

I’d still consider this for taking photos of architecture since distortion isn’t so bad. Just shoot this at the middle of the zoom’s range and that should even give you less distortion.

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It certainly performs better when shot with film, I think this is the best way to enjoy it. If you love using film I highly recommend this lens so long as you’re aware of its limitations.

I’d skip this and get the Zoom-Nikkor 35-70mm f/3.3-4.5 Ai-S instead, the latter is smaller and performs better. I won’t mind using a variable-aperture lens at all if it’s better. This one is for people who prefer to shoot with a lens that renders things with a certain “look”, maybe videographers will find this useful. If you really want to buy this one make sure that all the rings turn smoothly and the iris is dry and snappy when actuated. The lens should be clean and clear, too. These don’t cost much these days and they should give you plenty of good times and memorable photos so long as you know what you’re looking for. With that said do note that my lens came in terrible condition so that contributed to some image quality issues. If you read reviews and opinions of the numerous people who have used this lens you’ll see an opposing views, too. Don’t treat my article as the truth and it’s up to you to do some more research about this. Happy hunting.

Before We Begin:

If this is your first attempt at repairing a lens then I suggest that you check my previous posts regarding screws & driversgrease and other things. Also read what I wrote about the tools that you’ll need to fix your Nikkors.

I 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 novice. Before opening up any lens, always look for other people who have done so in YouTube or 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 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. It has a lot of useful information, it will be beneficial for you to read this.


This is a zoom so we couldn’t easily separate it down to its major components. The standard thing to do with zooms is to separate the optics first by assembly as you go along stripping the lens down. This is complicated but compared to later zooms it’s quite simple since it doesn’t have any complicated gimmicks. You may have to apply some alcohol or heat to the screws or threads in order to soften their seals before you remove them since this was made at a time when Nikon went crazy and applied plenty of glue to seal their lenses. Some of the seals are tough to remove because epoxy was used and only heat will soften them up. Having said that, it is not a lens for a beginner to work on. You’ll require special tools and the experience to decide on what to do if things didn’t go your way.

This isn’t a complete teardown article, I think I’ve lost about half of my notes since my old iPhone died. This is not an issue because most of what’s left are the important bits. You can also read my other repair articles, they will be helpful in figuring out how to further dismantle this.

Extract this to remove the front barrel.

Unscrew it, if this is stuck place a drop of alcohol to its threads to soften the seal up.

You can further dismantle the front barrel if you wish.

Unscrew the front optics assembly. Be sure not to misplace or warp the brass shim.

Extract the screws of the bayonet mount so you can remove it. Many people get stuck here because they don’t have the right tools and strip the screws. To prevent this from happening to you, read my article about how to remove bayonet screws. Follow my guide and that should help educate you on how its done and which drivers you should use.

Note that some of the screws are smaller than the rest, don’t forget to put these back where they belong.

Remove the base, aperture ring and the bayonet mount.

Carefully remove the shims and don’t misplace or damage any of them. These shims adjust the rear-focus and losing one of them will make your lens focus incorrectly.

This is how things should be.

Don’t forget the sequence in which these should be installed.

Extract the screws of the grip in order to remove it.

Study how the intricate mechanisms here work so you’ll know how to put it back properly later again.

Take plenty of notes so you’ll know how to put them back later.

This is how it looks like when zoomed.

Carefully remove the rubber part of the focusing ring.

Locate and extract this.

It’s small and delicate so don’t damage it.

Extract these in order to remove the keys.

Be sure to note the height and alignment of the inner barrel.

Remove the focusing ring.

Remove the distance scale.

Separate the helicoids. Don’t forget to note where these separated, this is also the same spot where they mesh. People forget to do this and waste a lot of time later figuring how to put these back. To help prevent this from happening to you, read my article on how to work with helicoids.

Remove the sleeve.

Carefully remove the rubber part of the zoom ring.

Extract these pins carefully.

Take plenty of notes before you go any further.

Extract these screws to remove the guide of the cam.

Extract these, too.

Carefully remove the outer barrel.

Remove the cam. Note that there’s excessive grease applied to it, this is not a good sign.

You can dismantle it further by removing this.

Clean everything well and don’t leave any residue. Since this only has a pair of helicoids I applied a thick type of grease so I could precisely focus with it. Never apply too much as that will create a mess and cause an even bigger trouble later when the oil migrates to the iris and optics. Only apply a thin film where needed such as the helicoids. Contact surfaces will require even less grease, you don’t want to leave a messy goo inside of the barrel.

Clean the glass carefully. If your lens has fungus, read my article on how to clean lens fungus. Don’t use the solution at full-strength, thin it with distilled water. Don’t soak the elements in the solution for too long or it will dissolve the coatings. The cemented group is fragile so handle it with a lot of care.


This took me around 2 nights to work on with most of that time spent cleaning the parts and reassembling the barrel. This will entertain advanced hobbyists but beginners should stay-away from this. Despite being simple compared to newer zooms it still requires plenty of thought and effort to service this.

Backtrack your steps to reassemble it but leave the front barrel out. Adjust the focus until you get it right, the long-end should be your priority and then adjust for the wide-end. Read my article on adjusting a lens’ focus if you don’t know how it’s done, that will show you how it’s done in a DIY setting.

Thanks for following my work, if you liked this article please share this with your friends so it will get more views. This site earns around $1.10 a day, it’s totally reliant on views. You can also support this site, it helps me offset the cost of maintenance and hosting. You are also helping me purchase, process and scan film. This site promotes the use of film so we’re all in this together. See you again in the next article, Ric.

Help Support this Blog:

Maintaining this requires resources to operate. If you think that this has helped you or you want to show your support by helping with its upkeep, make a small donation to my at 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.

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Thank you very much for your continued support!


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’s name or other information so that the donations will totally be anonymous. 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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