Nikon F4: Quick fix for gummed mechanics parts?

Andreas Thaler · Dec 1, 2023

BMbikerider said:
Do it yourself and make a mess of what you are doing then you have lost out big style and no comeback.

Because you mention costs:

A mint F3/T like mine costs around 1000 USD on the market. For the money you get four mint F4

BMbikerider said:
Why take a gamble?

Some people jump off the bridge using a rubber rope, others drive car races and I try my hand at repairing complicated cameras. We all have fun doing it

No offense at all, but „Why DIY?“ is my very favorite topic

Mamiya_Repair · Dec 1, 2023

The issue with the aperture lever you are having is not uncommon. From my experience servicing the F4, this is almost always caused by the ratchet gear on the side of the mirror box. It needs very light lubrication, just one drop of oil on the gear shaft. Unfortunately, there is no way to reach this part without removing the mirror box, no shortcuts. Squirting lubricants into the camera will not fix the issue and only cause more problems as the lubricant gets in places it does not belong.

Andreas Thaler · Dec 2, 2023

Mamiya_Repair said:
The issue with the aperture lever you are having is not uncommon. From my experience servicing the F4, this is almost always caused by the ratchet gear on the side of the mirror box. It needs very light lubrication, just one drop of oil on the gear shaft. Unfortunately, there is no way to reach this part without removing the mirror box, no shortcuts. Squirting lubricants into the camera will not fix the issue and only cause more problems as the lubricant gets in places it does not belong.

Thanks for this information! What are your experiences with disassembly/assembly?

It is completely clear that problems have to be solved professionally, but in this case, as I said, I see a high risk of damaging or misaligning the camera if I disassemble it.

I continue to monitor my F4 to see if anything changes after treatment with Zippo/graphite. If it turns out that this made the situation worse, I'll have to use the screwdriver anyway. But then it is clear to everyone who is interested in the topic that this was the wrong approach. I don't expect any negative effects from graphite because it doesn't spread itself. It is just difficult to clean. Things are looking good at the moment.

It is similar with the Canon A cameras, which developed “asthma”, the squeaking noise when the shutter is released. The quick fix is a drop of oil with a syringe. But if there is contamination, that doesn't fix it.

There is a second problem with the otherwise mint F4. The display in the DP-20 viewfinder has leaked and there is an orange line across it. The display that sits in the F4 also has black spots. These are also known problems with the F4 that can only be solved by replacing the displays - if you have a spare part.

I read somewhere that the cause of this is heat, which damages the displays. Since I don't store my cameras above 30 degrees Celsius (= 86 F), this should be out of the question.

Andreas Thaler · Dec 2, 2023

I looked through @F4user‘s tutorial again, especially the individual components that need to be dismounted. It's a lot of work, but it should be manageable with time and accurate image documentation. Removing the locking rings is certainly tricky; they can quickly become bent or the tool can slip.

So I'm going to attempt the disassembly, but first I'll do it on a worn out F4 that has the same problem.

What I really have concerns about is whether the camera adjustments will still be correct after assembly. But that remains to be seen.

My quick fix with Zippo and graphite improved the situation, the small apertures now continue to close. However, the aperture is a bit too slow and the mirror does not go all the way up in certain positions of the camera. So I have to take the long journey. If it works, I'll take on this F4.

Just the right activity for long winter evenings. We are currently having snow in Vienna

Andreas Thaler · Dec 4, 2023

Sometimes just not tackling something is already a success.

That's what I'm feeling at the moment with an F4 that I want to dismantle to fix the problem with the resinous mechanics in the mirror box.

The camera, with its smooth, velvety shimmering surface, doesn't invite you to open it.

I already failed when I tried to unscrew the rewind crank. The screw head is soft, I see brass shimmer, the screwdriver doesn't grip.

In order not to destroy the screw head pointlessly, the project ends here. Because I don't think the numerous other disassembly stages are any easier to master.

And my motivation to continue here is also greatly dampened by the condition of the two LCDs.

There's nothing left to do here.

It's a shame, the F4 is a wonderful camera, but you have to be able to say goodbye.

Andreas Thaler · Dec 4, 2023

This makes me think further about whether my fix with Zippo and graphite has potential. At least I was able to improve the other F4.

I'll put the topic on my project list and close it for now.

forest bagger · Dec 4, 2023

Andreas Thaler said:
I'll put the topic on my project list and close it for now.

Thanks for this report, Andreas!

Andreas Thaler · Dec 4, 2023

forest bagger said:
Thanks for this report, Andreas!

You‘re welcome!

Maybe I can think of something else to get the aperture mechanism going again.

Anyway there is always a last option

forest bagger · Dec 7, 2023

Yesterday I refurbished a very old (80 years!) EXAKTA by using WD-40...

Andreas Thaler · Dec 7, 2023

forest bagger said:
Yesterday I refurbished a very old (80 years!) EXAKTA by using WD-40...

How did you apply it?

forest bagger · Dec 7, 2023

Just like your picture shows it, through the shutter release button.

Andreas Thaler · Dec 7, 2023

forest bagger said:
Just like your picture shows it, through the shutter release button.

You used WD-40 even though it has such a bad reputation for camera repairs? What were your thoughts?

forest bagger · Dec 7, 2023

For me WD-40 and other "creeping oils" have no bad reputation.
In most cases I use "SONAX SX90 plus" and sometimes - hint - I mixed it with motor oil 5W40.

Andreas Thaler · Feb 3, 2024

Good news!

I just tested the F4, which I had „vaccinated“ with Zippo lighter fluid/graphite.

The small apertures 16 and 22 continue to close correctly. The aperture may not close as quickly as it should, but this is hardly noticeable.

The aperture lever in the mirror box still does not go all the way to the end.

This means that I have at least achieved some improvement using this method.

From here you could work further and repeat the procedure, with a higher proportion of graphite.

Very encouraging

Andreas Thaler · Feb 4, 2024

However, I would prefer to solve the problem correctly and that can only be done with disassembly, cleaning and new lubrication. But if I fail at the first screw when disassembling the camera, it won't work.

On the other hand, it is practice that determines whether a camera can be used for work. So I'm making this F4 my companion for the near future and will see what the results are on film.

If the aperture does not close quickly enough, this can cause overexposure at short exposure times because the aperture is not yet at target value while the shutter is already closed. This has a greater impact at 1/8000 s than at 1/30 s because the ratio overexposure/exposure time is adverse.

Andreas Thaler · Feb 4, 2024

In practice, such a situation can play a role if small apertures and a short exposure time are required due to the lighting conditions/ASA number.

This is rather unusual in my application, as I usually photograph in balanced lighting conditions and avoid small apertures due to diffraction effects/blurring.

Andreas Thaler · Feb 5, 2024

Since I was now able to loosen the first screw (rewind crank) on the second F4 with aperture problem, I will try dismantling it to remove the resin in the mirror box mechanism.

For this I'll be following this excellent tutorial by @F4user and the disassembly guide in SPT Journal:

Nikon F4 aperture lever repair

WARNING : Those instructions are for skilled persons with some knowledge of mechanics and electronics. Don't follow if you are unsure about your skills. F4 Aperture lever problem driving the lens down. This will be a long thread with ~100...

www.photrio.com

SPT Journal: January-February 1993

Society of Photo-Technologists Journal

learncamerarepair.com

If all screws can be removed, disassembly and assembly should be possible with meticulous documentation.

This will take me longer than a day and I need to be well rested.

If things go wrong, I'll be prepared because I follow these considerations:

Shortcut with Zippo lighter fluid/graphite brought a partial improvement but not a final solution.
There is therefore no way around dismantling it.
Nikon will not accept the F4 for repair.
A workshop will probably charge more for the work than the camera is worth.
If I leave it as it is, exposure problems are to be expected.
In any case, I will learn a lot from this project,
so GO!

Andreas Thaler · Feb 10, 2024

I thought about it again and compared my F4 with another one that was new. Here too, the small apertures close slightly delayed, but completely.

I'll test with film if this actually affects the exposure.

Otherwise, I will rarely take photos with these apertures as they are not ideal due to diffraction effects. And therefore dismantling a caliber like the F4 in 22 steps is not worth the risk.

I think this is also about the general attitude towards repairs.

You have to think carefully about whether you only accept a perfect camera for photography or collecting or whether you can do it with less than 100 percent.

In any case, DIY always means the risk that the camera will become inoperable, and a professional repair is also not without risk and costs money.

In any case, I was able to at least restore the aperture function using the Zippo/graphite method without causing any noticeable damage to the camera.

Andreas Thaler · Feb 20, 2024

In I'm currently reading about the shutter release sequence of an SLR, i.e. what happens after you press the shutter button.

Accordingly, cameras with sophisticated automatic exposure systems measure the exposure again at the working aperture before the mirror folds up and releases the shutter.

This means that any final changes in lighting conditions are taken into account.

With the F4, this would ensure that a slightly delayed closing of the small apertures would be compensated for by a slightly shorter exposure time. Although I don't know when the camera considers the aperture to be closed.

Anyway, a practical test with film will show whether it is so.

Norman Goldberg, The Dark Side of the Lens

forest bagger · Feb 20, 2024

This may be a way to handle with slowly closing aperture blades or aperture levers which are not completely going down.
But that would be a cure of the symptoms of these defects, no repair!

Andreas Thaler · Feb 20, 2024

forest bagger said:
This may be a way to handle with slowly closing aperture blades or aperture levers which are not completely going down.
But that would be a cure of the symptoms of these defects, no repair!

Of course this isn't a repair.

But as I wrote above, the alternative is to remove the F4 mirror box in 22 steps. There is a corresponding risk of this going wrong.

Would you take the risk for minimal functional impairment?

forest bagger · Feb 20, 2024

Of course not, too.
In my humble oppinion you should be content with these ~ 90% functionable cameras as long they do their work.

Andreas Thaler · Feb 20, 2024

forest bagger said:
Of course not, too.
In my humble oppinion you should be content with these ~ 90% functionable cameras as long they do their work.

I'm glad that I at least got the small apertures to close again using the Zippo/Graphite method.

Andreas Thaler · Feb 22, 2024

Today we're going into practical testing to see whether the F4 exposes properly after treatment with Zippo/graphite.

A Portra 800 is inserted that has expired for two years, but has been in the refrigerator for this period.

For the first time I am using the C-41 process from the Italian manufacturer Bellini in the Filmomat. I have already programmed the Filmomat accordingly for 3-bath development.

I will convert the scans from the Nikon Coolscan 5000 with SmartConvert, also for the first time.

So it will be exciting days!

Andreas Thaler · Feb 22, 2024

The work is progressing.

An older film and the test film from the F4 are currently being developed in the C-41 process.

The Filmomat is busy bringing the solutions up to temperature.

Nikon F4: Quick fix for gummed mechanics parts?

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