I noticed it on my first trip with the zoom: the smallest aperture of 32 was not formed on my Nikon F3/T.
It didn't close or open completely, but the next smaller 22 did without any problems.
I debated for a long time whether I should try to fix this.
Because I don't take photos with the smallest aperture anyway, and every intervention can cause new problems.
As always, I wanted it 100 percent and there is no budget for a professional repair.
Well then …
The candidate who gave me excellent results on the last tour cross the city.
Contamination?
I suspected a problem with dirt on the aperture mechanism.
Because when the zoom was retracted, the aperture 32 closed more reliably than when it was extended.
The aperture value set on the aperture ring is transferred via a lever in the tube. The longer the journey, the more friction becomes noticeable. If there is dirt in the gearbox, that can be enough to impair its proper functioning.
First I tried using Zippo lighter fluid to make the accessible part of the shutter mechanism more moving. But that gave not the desired result, the aperture continued to stick. An interlude of two drops of silicone oil made the problem worse, so I removed the oil again with Zippo.
So I had to
Grab a screwdriver
To access the aperture mechanism, I dismantled the lens from the back.
The place has been reached.
The marking shows on the left the lever that transfers the set aperture value to the aperture register.
The lever on the right closes the aperture when you press its small wheel. The Adaptall-2 adapter is connected to it.
I removed the left lever and after a few tries I was able to put it back in correctly.
And that solved the problem instantly, the aperture now worked as it should
Perhaps the position of the lever, which is attached and adjusted with two screws, was no longer correct. Or had dirt actually come loose?
I don't know it.
Adjustment of the aperture
When screwing the lever tight, I set the aperture to the largest to be able to align the aperture blades. If they disappear in the aperture register when the zoom is extended, it is correct.
In the retracted position they protrude slightly - this is achieved using a control cam to adjust the aperture to the set focal length.
A comparison with a similar Tamron zoom confirms this.
While looking at the rear optical unit, I noticed these neat artifacts.
It could be lens separation. Or the cement is not even.
There is no order for me.
This could be repaired by Optik-Labor in Germany, but the costs do not bear any reasonable relation to the market value of the lens.
In any case, I didn't notice anything disturbing in the last photos I took with the lens.
Assembly
This spring came loose from the aperture mechanism when the aperture ring was moved, namely below the bayonet. The ring jammed and one end peeked out. I couldn't figure out where the spring was inserted.
Of course that's not fine, but I didn't notice any functional impairment after removing it.
So it stays outside and hopefully everything stays peaceful in the lens.
The service manual would have been helpful here to determine the position and function of the spring. But unfortunately I don't have it.
Aperture 32 now fully functional.
The next photo excursion will show whether the repair was actually successful.
I wanted to look through the Tamrons in the background, but as always it took longer than expected.
Next time then
Conclusion
There were several times when I thought I had lost the lens:
But then, thanks to my own stubbornness, it worked
+++
All information provided without guarantee and use at your own risk.
It didn't close or open completely, but the next smaller 22 did without any problems.
I debated for a long time whether I should try to fix this.
Because I don't take photos with the smallest aperture anyway, and every intervention can cause new problems.
As always, I wanted it 100 percent and there is no budget for a professional repair.
Well then …
The candidate who gave me excellent results on the last tour cross the city.
Contamination?
I suspected a problem with dirt on the aperture mechanism.
Because when the zoom was retracted, the aperture 32 closed more reliably than when it was extended.
The aperture value set on the aperture ring is transferred via a lever in the tube. The longer the journey, the more friction becomes noticeable. If there is dirt in the gearbox, that can be enough to impair its proper functioning.
First I tried using Zippo lighter fluid to make the accessible part of the shutter mechanism more moving. But that gave not the desired result, the aperture continued to stick. An interlude of two drops of silicone oil made the problem worse, so I removed the oil again with Zippo.
So I had to
Grab a screwdriver
To access the aperture mechanism, I dismantled the lens from the back.
The place has been reached.
The marking shows on the left the lever that transfers the set aperture value to the aperture register.
The lever on the right closes the aperture when you press its small wheel. The Adaptall-2 adapter is connected to it.
I removed the left lever and after a few tries I was able to put it back in correctly.
And that solved the problem instantly, the aperture now worked as it should
Perhaps the position of the lever, which is attached and adjusted with two screws, was no longer correct. Or had dirt actually come loose?
I don't know it.
Adjustment of the aperture
When screwing the lever tight, I set the aperture to the largest to be able to align the aperture blades. If they disappear in the aperture register when the zoom is extended, it is correct.
In the retracted position they protrude slightly - this is achieved using a control cam to adjust the aperture to the set focal length.
A comparison with a similar Tamron zoom confirms this.
While looking at the rear optical unit, I noticed these neat artifacts.
It could be lens separation. Or the cement is not even.
There is no order for me.
This could be repaired by Optik-Labor in Germany, but the costs do not bear any reasonable relation to the market value of the lens.
In any case, I didn't notice anything disturbing in the last photos I took with the lens.
Assembly
This spring came loose from the aperture mechanism when the aperture ring was moved, namely below the bayonet. The ring jammed and one end peeked out. I couldn't figure out where the spring was inserted.
Of course that's not fine, but I didn't notice any functional impairment after removing it.
So it stays outside and hopefully everything stays peaceful in the lens.
The service manual would have been helpful here to determine the position and function of the spring. But unfortunately I don't have it.
Aperture 32 now fully functional.
The next photo excursion will show whether the repair was actually successful.
I wanted to look through the Tamrons in the background, but as always it took longer than expected.
Next time then
Conclusion
- Only reluctantly did I get to work. Because as soon as it starts to be dismantled, new problems lurk.
- And I want to limit my repair activities for A lenses, those that are valuable to me, to only the bare essentials.
- As always, the candidate said goodbye beforehand, so that work can be as carefree as possible.
- If it works, then it works, and if it doesn't, then it doesn't. This is the most important rule when doing repairs yourself
There were several times when I thought I had lost the lens:
- Cleaning with fuel didn't help fix the problem.
- A spring that is no longer in its place, but is on the table, doesn't give you any extra courage.
- And as I struggled with the lever in the tube, I felt queasy.
But then, thanks to my own stubbornness, it worked
+++
All information provided without guarantee and use at your own risk.
