Canon nFD 28/2: Outsmarting and cleaning the aperture blades

[Andreas Thaler]

For years, oil has been shining at me when I look at the aperture blades of my fast wide-angle lens.

And this has saddened me for years.

This should be over now

One of my favorite lenses and quite heavy.

The rear optical unit can be easily unscrewed and is already removed here. The aperture blades are now exposed.

The aperture still closes properly, but there shouldn't be any oil visible here.


Outsmarting the aperture

With a Canon nFD lens, when removed, the aperture is in a fixed position.

Opening and closing, such as with Minolta MD or Nikkor Ai(-s), is not possible.

However, the aperture blades cannot be cleaned because moving the blades through is part of the cleaning process.

To do this, a Canon FD back cover must be cut open.

The remaining ring simulates the lens bayonet.

Once the ring has been screwed in and clicked into place with an audible click, the aperture on the lens can now be opened and closed using the aperture lever.

I prepared a back cover in this way using a Dremel with a cutting-off wheel.

So that the ring can be screwed all the way into the lens bayonet, I removed the small nose on the bayonet of the ring. (Actually, with nFD only the barrel of the lens rotates. The camera and lens bayonets remain aligned.)

Inserting the ring ...

and screwed in.

The lens now behaves as if it were mounted on the camera.

See also

Canon New FD: from bayonet ring to aperture key

A special feature of Canon New FD lenses is that their aperture remains fixed at a value as long as they are not attached to a camera. The aperture blades cannot then be moved and checking the optics and aperture blades with an LED lamp is only possible to a limited extent. “Aperture key”...

www.photrio.com

The aperture can now be opened and closed using the aperture lever.

When idle, the aperture is open.

The elements of the rear lens unit.

The lens under the aperture is very tight and a bit cloudy.

I'll clean it after the aperture blades.

Treatment of the oily aperture blades with Zippo lighter fluid.

After a few passes with Zippo, opening and closing, wiping off the dissolved oil and drying with the hot air tool, the blades are clean.

What still shines after drying is oil because the Zippo evaporates.

Therefore, the process must be repeated until the shine is no longer visible.

Now the lens under the aperture can be cleaned.

There are also Zippo/oil streaks from cleaning the aperture blades.

Remove fog and streaks with isopropyl alcohol, cleaning swabs and lens cleaning cloth.

 

[Andreas Thaler]

Reassembled

This treatment does not finally resolve the problem with oil contamination. This would require dismantling the lens, removing all oil from the tube and relubricating the helicoids. An effort that is too great for me. I'd rather clean the aperture blades again when the time comes.

As long as the oil doesn't affect the movement of the aperture blades, it should not bother me too much.


+++

All information provided without guarantee and use at your own risk.

 

[campy51]

I know this is an old thread but this is how I would do it. Not that yours is wrong but mine I think will clean it better. I would remove front and rear lenses and use a good electronic spay like the one below. Close the blades down and give a good spray front and back and work the blades open and closed several times to get the cleaner inside were the oil is coming from and on the post the blades sit on. Do this repeatedly and then lastly clean the blades as you did. Now for the lawyers, do this at your own risk.

 

[Andreas Thaler]

I know this is an old thread but this is how I would do it. Not that yours is wrong but mine I think will clean it better. I would remove front and rear lenses and use a good electronic spay like the one below. Close the blades down and give a good spray front and back and work the blades open and closed several times to get the cleaner inside were the oil is coming from and on the post the blades sit on. Do this repeatedly and then lastly clean the blades as you did. Now for the lawyers, do this at your own risk.

Interesting, thanks

That's electronics cleaner? How does it work better than lighter fluid?

 

[campy51]

It evaporates very quickly and leaves no residue. I use it all the time on shutters, especially the slow speed assembly, but you usually have to oil the tiny post after.

 

[Andreas Thaler]

It evaporates very quickly and leaves no residue. I use it all the time on shutters, especially the slow speed assembly, but you usually have to oil the tiny post after.

Great, I'll try that too, I think it doesn't matter which electronics cleaner you use.

I've known that these products dissolve grease since I once tried to remove resin buildup in the mechanics of a Nikon F4's mirror case.

This worked well at the beginning, but when the dissolved grease was gone or became hard again, the problem was bigger than before.

 

[campy51]

I don't think I have used it on heavy grease, just the light stuff and oil, also works great on getting labels off.