Nikkor 600 F4 problem

[Onslow]

Morning all,
A good friend of mine has a approx 2yr old AF-S Nikkor 600mm 1:4G ED lens. It has had approx 28000 images according to LR info. My friend asked for some advice the other day. The viewfinder was dark and it was hunting. I had a look at it yesterday.
What I found was a dark viewfinder compared to other cameras with different lenses at f4. We tried swapping onto a D3s, D700 and a D200. All showed the same.
I then tried the DoF preview which wasn't working on the 600 on any camera but was on the other lenses. We then took the lens off the camera and I looked through to the aperture. It was not wide open as I would have expected but approximately 5mm in diameter. Probably down around f16-22, in that range. I did not see it change size at all through the tests. I also tried cleaning the lens contacts with no effect.
I have no experience with this lens but believe it would still meter/focus at f4 and snap down to the aperture selected when the shutter button is fully pressed.
So, I believe that something has occurred with the aperture control.
Would anyone know of any known problems like this or is he stuck with it to go back to Nikon?

[synn]

Sounds like a stuck aperture. Needs to go back to nikon, unfortunately.

[Onslow]

Sounds like a stuck aperture. Needs to go back to nikon, unfortunately.

Cheers, I do agree. I was wondering if this is a known problem or just one of those things.....

[telyt]

Is the aperture control fully electronic or does the body stop the lens down via a lever at the back of the lens?

If the latter the lever might have become disconnected from the diaphragm.  It was a surprisingly flimsy metal tab on my 300mm f/4 ED AF that I was able to bend back into position in 5 minutes.  The local authorized repair center wanted $350 to do the job.

[Onslow]

Is the aperture control fully electronic or does the body stop the lens down via a lever at the back of the lens?

If the latter the lever might have become disconnected from the diaphragm.  It was a surprisingly flimsy metal tab on my 300mm f/4 ED AF that I was able to bend back into position in 5 minutes.  The local authorized repair center wanted $350 to do the job.

It appears to be a fully electronic control. No sign of a lever to move the diaphragm sadly...

[Lilien]

It appears to be a fully electronic control. No sign of a lever to move the diaphragm sadly...

There's no 600 mm f/4 with electromagnetic diaphragm, so if you can't find the lever it seems to be lost.

Regards, Juergen

[BernardLanguillier]

Indeed, the only current Nikon super tele with Electromagnetic diaphragm are the new 400mm f2.8 E and 800mm f5.6 E.

Of course I di expect Nikon to update the 200mm f2.0, 300mm f2.8, 500mm f4 and 600mm f4 soon, but that won't help the OPs issue.

Sending the lens for repair may be the best option. The only major failure I experienced with a Nikon item in ~30 years of merciless usage was aperture related with a 70-200 f2.8.

Cheers,
Bernard

[Onslow]

There's no 600 mm f/4 with electromagnetic diaphragm, so if you can't find the lever it seems to be lost.

Regards, Juergen

Jurgen, Thanks for that, I checked the back of the lens and compared it to his 200-400 Nikkor. The 200-400 diaphragm lever has what feels like a return spring on it so when it moves, the lever snaps back when released. Checking this against the 6600, I found the same lever floppy, no spring feel to it at all and just moves around so I suspect there is a problem in that section of the lens. Hopefully, not too expensive to repair.
Cheers for the idea.

Indeed, the only current Nikon super tele with Electromagnetic diaphragm are the new 400mm f2.8 E and 800mm f5.6 E.

Of course I di expect Nikon to update the 200mm f2.0, 300mm f2.8, 500mm f4 and 600mm f4 soon, but that won't help the OPs issue.

Sending the lens for repair may be the best option. The only major failure I experienced with a Nikon item in ~30 years of merciless usage was aperture related with a 70-200 f2.8.

Cheers,
Bernard

Thank you for that info Bernard, that helps assist with what I found in my reply above to Juergen.