lens streaks

[Noah B]

I recently got a fujinon w 180mm lens and went to clean it before use today and noticed some streaks inside the lens. I cleaned both side of front and rear elements but the streak seems to be on the inside of the rear glass. Is this a common occurrence? Any ideas how to get rid of it?

[E. von Hoegh]

Your streaks are probably the result of sloppy cleaning of one of the inner glass surfaces. Get rid of the streaks by cleaning properly whichever surface they are on.

[cyrus]

Actually, the way you describe it, you may be talking about lens separation rather than streaks.

[E. von Hoegh]

Actually, the way you describe it, you may be talking about lens separation rather than streaks.

Hard to say without seeing the lens. I've noticed that most things in lenses are described as "fungus" and "separation". They're usually anything but. Actually, I've never personally seen a lens with fungus, and I've seen and handled alot of gear over about 40 years. I've seen - and removed - fungus from just about every other part of a camera. Reading on the sites though, it seems every third lens has fungal colonies, and about half have separation. I once bought a 300mm Schneider Symmar for a song, it had "separation" - I figured I'd deseparate it. It had Schneideritus, a bit of Rustoleum flat black fixed that problem. Wierd.

[ic-racer]

The newer Fujinon 180mm lens with markings on the outside barrel is 6 elements in 6 groups, so there should be no glued surfaces.

[E. von Hoegh]

The newer Fujinon 180mm lens with markings on the outside barrel is 6 elements in 6 groups, so there should be no glued surfaces.

Yes, but the old one was a 6/4 Plasmat, wasn't it? That would leave one glued surface (separation) and two internal surfaces (for streaks) per cell.

[Dan Fromm]

E., have you ever looked at RR lenses in Folding Pocket Kodaks? Many have peripheral balsam faults that show as a golden crust.

Re separations, their presence seems to depend on the maker and era. Most of my Voigtlaender lenses from an automatic printing machine (as used by photofinishers, remember them?), my 58 Grandagon, a monstrous S.F.O.M. lens and an EKCo 25-15 converter for the 25/1.4 Cine Ektar II have spectacular Newton's rings. And I've had a 16/2.5 Luminar that had voids in the balsam; must have been baked ... I gather that Rodenstock and Voigtlaender had major problems when they switched from balsam to synthetic cements.

[E. von Hoegh]

E., have you ever looked at RR lenses in Folding Pocket Kodaks? Many have peripheral balsam faults that show as a golden crust.

Re separations, their presence seems to depend on the maker and era. Most of my Voigtlaender lenses from an automatic printing machine (as used by photofinishers, remember them?), my 58 Grandagon, a monstrous S.F.O.M. lens and an EKCo 25-15 converter for the 25/1.4 Cine Ektar II have spectacular Newton's rings. And I've had a 16/2.5 Luminar that had voids in the balsam; must have been baked ... I gather that Rodenstock and Voigtlaender had major problems when they switched from balsam to synthetic cements.

Yes I have Dan. I recemented one RR on a Kodak folder with balsam collected from local trees. I have a 32mm Micro Tessar by B&L which displays the Newton's rings. I had a Protar with the balsam ring as well.

My point was that fungus and separation seem to be the "go-to" faults whenever someone sees or hears of something inside a lens.

[Noah B]

I've got the model with the lens details on the inside of the front lens, it's the older one with the 300mm image circle.