Aperture ring question

[john341]

Hi all, I have a Ju-8 black lens, the model where the entire front rotates during focussing. I noticed that, wide open, the ring stops at f2.8! If I loosen the three miniature screws on the aperture ring, will I be able to move it safely to f2 ? Better to ask than to bring disaster. Thanks in advance!

 

[sevo]

Is the lens fully open when the ring displays 2.8, or can't you open the aperture to 2.0?
At least on my (earlier) silver versions you could re-seat the ring to have it display the proper values. But if you are stuck at a actual f/2.8, you'd have to remove more than just the aperture ring to get at the aperture stops.

 

[Rudybustamante]

When I removed the focus ring for some minor repairs (M39 J8), I over-tightened the 3 screws that hold it on, one of which made one end of the aperture values extremely difficult to turn.Loosening it a tiny amount sorted it all out

 

[john341]

Alas!

Alas!

The aperture is fully open at f2.8. Cannot move ring further toward f2. Aperture ring is easy to move and the silly part is that the lens has had no damage...can't understand what has gone wrong with...russian gremlins?? So simply removing the 3 tiny screws in the aperture ring isn't going to work?

 

[Dez]

If the aperture is fully open when the ring is at f2.8, can I assume that you can turn the ring way past f22?
If so, yes, you can fix it by loosening the three screws in the aperture ring and repositioning the ring so it shows the correct aperture. If the screws don't want to tighten all the way in, you may need to take a tiny drill, smaller than the existing holes, and make indentations for the ends of the screws. I wouldn't be surprised to find that there already such indentations in the correct position, and the aperture was messed up by a DIYer with more enthusiasm than skill.

Cheers,
Dez

 

[john341]

Fixed!

Fixed!

It was a very thin spacer ring which became detached from the lens body..its back where it belongs and now the aperture ring matches the white dot (whew)