Fuji 125/5.6 rear element problem

[Havoc]

I have a Fuji W 125/5.6 that I got because I liked the field of view and it can stay on the Wista when I fold it. So ideal for going light.

But this week I had it along with the just arrived CM/W 256/6.3 and I immediately notice a difference in "clarity" on the ground glass. The 250 is very visibly sharper, clearer, easier to focus etc. Now I took a better look at the 125 and what I saw was this:

http://users.skynet.be/sb262617/forum_foto/fuji_125_rear_element_sm.JPG

This doesn't look good. It looks far worse on the photo but I had a hard time getting it visible in the photo. I took the rear element apart and it is on the last cemented doublet. I cannot make sure if it is on the most rear surface or (worse) in the cement. I tried cleaning with alcohol and a microfiber cloth. And even with an ammoniac/peroxyde mixture but no change.

Any idea what this is? It doesn't look like fungus, I cannot see it as scratches either.

[Cor]

Hard to tell, but I have maybe the same problem as you, my Symmar 300 mm lens frequently hazes up, if that is the right word: In my case the fogging over took place WITHIN the rear group, I have to take apart the rear elements (in case of the Symmar it are 2 cemented elements, one is easily removed the other is fixed in the housing, now both inside, facing surfaces of the elements can be cleaned, dried, and carefully put together again (no dust!). No idea what is causing this inside fogging up, its seems almost a oily substance, or perhaps just water damp, I do not know..

good luck,

Cor

[Pfsor]

Balsam (or whatever optical adhesive was used) outgassing. The lines could be a sign that somebody tried to clean it or it was cleaned before and the evaporation followed the chemical traces after.

[Havoc]

Just to make sure I got it right, this is between both lenses of a cemented doublet. So the only way to fix it would be to take them apart. Not sure I'm going to risk that.

[Pfsor]

... Not sure I'm going to risk that.

That's a wise decision. You would loose the correct factory alignment of the lens cells.

[Louis Pacilla]

That's a wise decision. You would loose the correct factory alignment of the lens cells.

OK then but what does he have to lose?

[Pfsor]

OK then but what does he have to lose?

I don't know. Can he use the lens as is? Only he knows.

[Havoc]

I can use it, it is just a bit soft if I compare it to the 250/6.3.

[Pfsor]

Besides, buying another Fuji 125 would probably cost you less than a professional repair of the old one... Some lenses have a sad life.

[Pfsor]

And when I think of it - it would be probably the best solution to your problem. It's a lovely if a little bit forgotten focal length.

[Bernice Loui]

Lens cell appears to have cement separation. The individual elements would need to be de-cemented than re-cemented precisely on their optical center.

Suggest scrapping this Fujinon lens cell, keep the shutter if it in good condition, then purchase another 125mm lens to replace it.
Given the cost and resources involved with producing view camera images, there is little if any justification to continue using a less than optimal lens.


Bernice

[Cor]

Agree with above posters if the problem is between cemented lens cells..buy a new one, and perhaps experiment with the fogged group, there are post on this forum on separating and re-balseming (?) Getting a similar lens on ..bay, or perhaps through Kumar (on this forum, he sells from Japan, a great guy to deal with).

good luck, it is really a nice compact lens, I also have one and are very happy with it.

Best,

Cor

[JimL]

Aren't the Fujinon-W's 6 elements in 6 groups, so no cemented pairs? At the bottom of the OP's picture I can see a scratch by the notch in the retaining ring which tells me that the lens has been taken apart before. Probably nothing to lose by taking it apart again...

Edit... I realized NW were 6-6, older W's could be 6-4

[Havoc]

I made that scratch when taking apart. It really is a cemted doublet, I can see the line at the edge.