Repair: Nikkor-H 300mm f4.5 Auto

Hello, everybody! Hope you guys are fine, I had painful back problem yesterday because I slept in the wrong position. Back pain has always been a problem of mine for years and it comes back occasionally. It’s probably due to the nature of my job where I am required to sit for long hours at work. Repairing lenses and cameras isn’t much help too because I am spending a couple of hours a night sitting in a bad posture. Speaking of back pain, I’ll show you guys a lens that will certainly make your back ache if you are carrying one for too long and that’s the reason why I seldom use this lens.


Today, we’re going to talk about one of Nikon’s earlier telephoto big boys and it’s no other than the Nikkor-H 300mm f/4.5 Auto! This lens succeeded the Nikkor-P 300mm f/4.5 Auto  lens. They are nearly identical to each other except the early lens only has 5 elements. It was one-of-a-kind when the Nikkor-P 300mm f/4.5 Auto was released in time for the 1964 Olympics in Tokyo. It was then updated with an additional element in 1969 but its design remained nearly-identical. In fact, it can be hard to tell the difference when you have the 2 together in a picture. I don’t have the earlier lens but people claim that it’s a decent and well-balanced lens even wide-open. This lens is supposed to be the improved version but I cannot do any tests to back it up and my copy of this lens suffered from terrible damage in the rear element which seems to be somewhat common with this lens.

IMG_0037This is a big lens and it can get longer when you extend to built-in hood. It balances well on the Nikon D750 and I can imagine that it can be even better with a bigger camera like the Nikon D4. It’s not something that you will want to use today for sports and wildlife in situations where you will need blazing-fast AF performance and super-sharp images but it can be an enjoyable lens to use when you’re just playing around.IMG_2910The lens alone is a big and heavy piece of equipment but it’s tiny when you compare this with Nikon’s monster lenses that weigh 4kg upwards. This is the “gate-way drug” when it comes to long prime lenses, very much like today’s 300/4 family of lenses.

IMG_0255Its length can be a problem at times when it comes to storing or carrying it but the good news is you have a tripod foot (fixed only) so you can use a sling with it. The tripod foot’s 2 holes are oriented as such so you can attach your setup in portrait or landscape modes to suit your framing but having to reinstall it each time you change frame orientation is tedious so the next version of this lens came with a rotating tripod collar.

Now that you have a nice background of this lens, it’s time to see how this thing performs in real-world situations. I went to the zoo last weekend and I found the chance to use this lens. I will have to warn you beforehand that my sample has a damaged rear element so don’t take my samples seriously. The damage is so bad that it will definitely show in all of the pictures taken with this lens, just keep this in mind when viewing my samples.

HAW_2306Vignetting wide-open can be terrible but it won’t be this obvious in real use. You will not notice this unless you go out of your way to look for it.

(Click to enlarge)

These pictures were taken from f/4.5, f/5.6 and f/8 respectively. At f/4.5, the lens is decent but you can feel that the look is outdated in many ways because of all the flaws evident in the picture. You will see fringing and other sorts of imperfections. While the center is sharp where in-focus it’s still not as sharp as I hope. At f/5.6, things even-out a bit when it comes to resolution and sharpness but it’s still not a huge jump from f/4.5 but at least the fringing is now not as bad. Haze is also one of the things that goes away a bit and you can notice it instantly when viewing the thumbnails. By f/8, things really begin to look better. Resolution and sharpness has improved and contrast begins to pick-up.

The good news is this lens performs better when shooting at things further-away like the 1st set with the cranes. Sure, it still sucks compared to modern lenses but it’s pretty damn decent. I took some pictures of palm barks for the last set so we see any improvements in contrast, resolution and sharpness better. Looking at the pictures of the birds, I can say it is pretty acceptable at f/8. From my samples, you can say that f/8 is what you’ll want if it’s something important otherwise you can shoot at f/5.6 if you still wish to have nice bokeh.

(Click to enlarge)

Here are some pictures that I took. These were mostly shot at f/4.5 and you can see that it is decently sharp wide-open. You can also notice lots of magenta casts in the image. It can be nice when you shoot it in the right lighting condition but it’s mostly hit-and-miss. This lens also has a very long minimum focusing distance of about 2m. This is kind of useless for some types of portraiture but it’s perfect for full-body shots. The long focal length will also compensate for the lens’ rather slow maximum aperture of f/4.5 so you can get some smooth bokeh if you know how to compose your shot properly. Focusing can be a bit of a problem if your subject is close because hand-holding the lens can be difficult when you are not shooting in bright day light. You would want to use this lens with a shutter speed of no less than 1/300s ideally so you the effects of a shaking hand will somehow be less. I didn’t enjoy using this lens much to be honest.

The lens is a decent performer but is nowhere near what you can get with today’s lenses. Even the cheaper zooms will out-perform this lens in every situation. I don’t see why you would want this lens today apart from collection and wanting to try something new. It’s a lens that has lost its usefulness for practical situations but lives on in the hearts of many collectors and hobbyists. Let’s now begin with our repair article!

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 now-growing 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 (Front Barrel):

Firstly, I would like to apologize if this article is going to be confusing for some. I lost lots of images when my old iPhone died and these are all I have. The order of the images will also not make a lot of sense because they weren’t taken in the correct order but I will try my best to make sense out of these so please bear with me. Thanks for the consideration.

This section will likely take up most of your time. I hate working with bigger lenses like this one because the parts are obviously bigger and these are usually sealed with glue or paint on some vital parts and retainers. I will not recommend this lens to beginners due to the fact that the glass is bigger on this lens and you will require special openers just to open some of the parts here. These are mostly openers and spanners that are bigger than your average-sized ones and you may have to fabricate some yourself.

Like all lenses that we work on, we will want to separate the optics first so we can safely work on the rest of the lens without worrying about accidentally scratching anything. We will separate this lens into 2 sections with the usual section for the objective consolidated into the part for the front barrel because the construction of this lens is such that they’re designed as a single unit. You can read my article on the Nikkor-Q 200mm f4 Auto since it is similar to this lens in terms of construction.

If there’s something that I would like to caution you with this lens is that one of the rings or collars here has a reversed-thread meaning you will have to turn it the other way just to loosen it. I forgot which one that is but it’s somewhere around the neck of the lens. Just do a quick check by turning the ring both ways and see which way it will work.

IMG_0253To separate the front part of the lens from the main barrel, you must first unscrew a set screw at the lens’ throat. The screw secures the collar which you can rotate until the lens separates into 2 parts. Mine was not easy to remove and I had to use some rubber strips to help me grip the parts. Drop some alcohol or solvents into the hole to soften the bond. Remember that I mentioned that one of the rings or collar in this lens should be rotated the other way in order to loosen it? Well, this may be the one that I was talking about.

IMG_0231You have now separated the lens into its 2 basic components. Set the main barrel aside as you work on the front barrel.

IMG_0200Remove this set screw that secures the collar with the name and serial number.

IMG_0214Remove this set screw so you can remove the sleeve. The sleeve comes off together with the hood as a single unit and it slides towards the the rear over the engraved collar. Like what I mentioned before, I forgot which of these collar should be turned the other way in order to loosen it so try turning everything in the front barrel in both directions to see if any of them turns the other way.

IMG_0034Now, I am not how I got this off but it involved rotating the sleeve underneath the hood. I also recall turning the collar with the engravings. Remember, one of the collars here is a reverse-threaded collar so you will have to turn it clockwise in order to loosen it. Try to turn a collar both ways and see which way it can be loosened.

IMG_0032The hood can now be further disassembled into its bare components. The spring and ball you see here is used for the clicking mechanism on the hood. These are housed inside the chrome button on the hood. If I am not mistaken, there is a small metal cup between the the spring and the nylon ball. That cup is not in this picture.

IMG_0035The front comes off just like this after you remove the small set screw. It houses the front elements assembly so handle this with care.

IMG_0026You will have to first remove this huge retention ring. It can be difficult because of its big diameter you will have to use a larger spanner for this. This can be very tough to remove so just repeatedly place a drop of solvent at the seam and let that work on the dirt or the paint that is keeping you from removing it. If yours came off easily, congratulation!

IMG_0240Mine came off just like this but not without plenty of effort.

IMG_0236The 1st and 2nd elements were cemented into a doublet and you can extract it with a lens sucker. The fit can be snug or loose so be careful not to drop this thing to the floor.

IMG_0028The 3rd element is a huge chunk of glass and you can remove it using a lens sucker. You should take some notes or use a pencil to make a small mark on the walls of the elements so you will know where they should be facing.

IMG_0025The 4th element is sealed with its collar or at least it seems like it. I carefully removed it from the back of the front part making sure that I don’t damage anything. Be careful with the shim. It’s made of something that appears to be gutta percha. It will dissolve quickly in alcohol if you’re not careful so clean this with care.

IMG_0031The broad collar can’t be removed it seems without major disassembly, I just left it alone. If you want to further disassemble the iris, I suggest you read the lens repair article that I wrote for the Nikkor-Q 200mm f/4 Auto. That lens has a lot in common with this lens in a lot of ways specially when it comes to the iris part.

IMG_0259The 5th and 6th elements are housed at the rear of the objective. The 6th element can be accessed by removing this retention ring. The 5th element inside can be easily removed soon after. You can unscrew the rear part of the objective’s housing to clean what’s in the housing if you wish.

That’s it for the front barrel. It isn’t awfully difficult now that I think about it. Maybe it is because I have gained experience with this lens so it seems easy to me now. I have gotten used to working with bigger Nikkors so I have the proper tools to work on them. If this is your first time to work on bigger lenses, just make sure that you fabricate the right tools.

Disassembly (Main Barrel):

While the previous section can be a bit frustrating, this section is going to be easy for you because the steps here will be ore familiar to you. Cleaning the parts can be a little but of a pain because they’re bigger but it shouldn’t be much of a problem for you.

IMG_0205The bayonet mount assembly can be removed by unscrewing its screws. If you’re new to lens repair, please read my article on how to remove screws from bayonet mounts. This is where many beginners get stuck so make sure you read it so you won’t make mistakes.

The bayonet mount assembly also includes the stop-down lever assembly. I seldom have the need to clean the stop-down mechanism. If it’s gummed-up or sluggish then that’s the time when I know that I need to clean the oil away.

IMG_0175I found this piece of cotton inside the main barrel and I don’t know why this thing’s here. The previous guy who worked on this sure left me a calling card (for his sloppiness).

IMG_0183Before you can proceed, you must remove this tripod foot because it’s in the way. You can feel that the metal is coated with rubber. It’s soluble in solvents and alcohol will lift it so be careful when cleaning this.

IMG_0223The focusing ring can be easily removed by unscrewing these screws, I think there are 5 of these around the circumference of the focusing ring.

IMG_0202The focusing ring can now be safely removed. You can only remove the focusing ring if it is not obstructed by the front part of the lens.

IMG_0155Once the focusing ring and the tripod foot is gone you can now remove the grip/sleeve. It is being secured by a couple of screws that you will have to remove first.

IMG_0195Once the shiny grip is gone, you can now access these 2 holes. These holes will help you get to the screws of the helicoid keys. Just turn the helicoid until you see the screws show up under the holes. Carefully remove the screws so you can free the helicoid key. The key is used to sync the movements of the helicoids so turning the central one will extend the helicoids. Collapsing or extending the helicoids will enable you to focus the lens.

Before you Go any further, make sure that you mark how the helicoids are line-upped. It is important to take as many notes as possible before you separate anything.

IMG_0216Oh, I totally forgot about the aperture ring! In order to remove it, you must first unscrew this. This screw acts like a pin to couple the aperture ring to the aperture fork under it.

IMG_0226Once that screw is gone you can now safely remove the aperture ring.

IMG_0207OK, back to the helicoids. Once the helicoid key is gone, you can now separate this into its bare components. For those who are new to this, make sure to read my article on how to work with helicoids. Many people get stuck here because they don’t have any experience or knowledge with these things. So long as you know where and how they separated it’s going to be OK. Remember to read my article and watch the video carefully.

This lens requires plenty of grease due to its size but don’t apply to much of it as to make it form a gloop around the edges of the helicoids from the excess grease. A light grease is ideal for this lens because of the long focus throw of this lens. A heavier type of grease is going to make turning the focusing ring a little bit too tough.


Thank goodness we’re done! This was a stressful article to write because my notes aren’t complete. I’d imagine that it was also stressful for you to follow this because the order of the pictures don’t make a lot of sense. Thanks for bearing with me on this, we will see a better article next week and I promise you that it’s going to be in-line with the quality of most of the articles here. Needless to say, this is an important lens that we have to tackle in this blog. I have been wanting to write this for a long time but I don’t like to use this a lot and I don’t find this as interesting to use compared to the other long lenses that I have in my small-time collection. It’s an interesting lens but I own more practical ones to use.

IMG_3354Here it is now! It sure made the Nikon D7200 look tiny! With the 1.5X crop factor of DX, it is going to be about 450mm with this setup.

See you guys again next weekend. I still don’t know what I am going to write next time so I will just leave it to my mood. Like I said in the last article, I am feeling burnt-out and it’s sometimes getting too much for me. Maybe I will go back to writing shorter articles next time and occasionally add more complex repair articles here and there. I probably need a small break and get back to writing lengthier articles.

Thank you very much for bearing with me and my rants and please come back again and read my next article. I would also like to thank everybody who donated and support this blog. You guys are all fantastic and you guys help keep me going on. I’ll dedicate the next camera repair article to you, you know who you guys are. See you again, 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.


Buy me a roll of film or a burger?

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 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.


1 Comment (+add yours?)

  1. Trackback: Report: Nikkor Prototypes (Part 5) | Richard Haw's Classic Nikon Repair and Review

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