Stuck front element ring

[Darkroom317]

I have a Schneider 210/370mm convertible lens. The front lens group has haze which has been getting worse since I started using the lens. I would like to clean the haze but it is between the elements. I can't get the front element ring off to get to the haze. Does anyone have any suggestions on how to loosen up the ring. I have tried using heat but it has not made a difference. Are there any compounds that I can use to loosen it that pose little risk to the glass? Thanks

 

[Leigh B]

That's not haze. it's fungus.

Time to dump the lens before it infects your other enses.

- Leigh

 

[AgX]

Heat should be applied selectively. Thus to the front part of the barrel, not to the retaining ring.

 

[Gerald C Koch]

Heat should never be applied to a lens group if it contains cemented elements. Doing so may cause the elements to come apart. I might also add that DIY repairs to a valuable lens are unwise.

 

[onre]

Dumping lenses because of fungus is just plain stupid. It can be removed rather easily. To loosen a stuck front ring, I've used different solutions ranging from lighter fluid to 1:1 acetone/ATF mixture applied sparingly to the thread. Also, good tools are a must here.

Leigh B, I can supply my address so you can send your fungus-infested lenses to me instead of dumping them. I can pay for shipping.

 

[AgX]

Heat should never be applied to a lens group if it contains cemented elements. Doing so may cause the elements to come apart. I might also add that DIY repairs to a valuable lens are unwise.

I said "selectively". It takes time form heating part of the barrel to heat up a cemented group.
Here are several posts of people who got a stuck helicoid with a Tesar type lens unstuck by means of heat.

 

[shutterfinger]

Heat should never be applied to a lens group if it contains cemented elements. Doing so may cause the elements to come apart.

Horse Feathers. Balsam has to be heated to 300°F or higher to separate the lens elements http://www.skgrimes.com/library/old-news/old-lenses-can-be-restored-by-re-cementing .

I might also add that DIY repairs to a valuable lens are unwise.

Only if you have 12 or 14 thumbs, you cur your fingers off on a table saw, with a router, on a power plane, or similar. I have thirteen thumbs and they work well with lens and other camera gear.

The retainer rings of lens may have a clear thread locker applied at the factory and will not budge until the thread locker is dissolved. Use a cotton swab saturated in Acetone/nail polish remover and wet the threaded area thoroughly then allow the lens to sit for 5 to 10 minutes before trying to remove the retainer. A second application may be necessary.

Heating a stuck lens or shutter: heat an oven to 250°F-275°F which is usually the lowest setting on most ovens then place the stuck part in the center of the oven, close the door and turn the oven off. Let the part sit in the warm oven for 15 to 20 minutes, remove from the oven using heat resistant gloves and allow to cool enough to be handled.

Symmar convertible lens diagram

other version of Symmar's have no air spaced cells, all elements are cemented.

 

[peter k.]

Horse Feathers.

Giddy up front element.. let go, let go and go ..
Turn with the sky and unleash the lens so it can be cleaned and see clearly the light from the sun, for a picture to behold..
Ya hoooo... ride em cowboy...

 

[Gerald C Koch]

Horse Feathers. Balsam has to be heated to 300°F or higher to separate the lens elements.

Of course there is no guarantee that Canada balsam was the cement used. There are others like Venice turpentine and several synthetic ones. Unless the present owner has had the lens since it was made there is a chance that it was serviced using modern cements. The fact is that one never knows. I consider it wise to use caution.

 

[Dan Fromm]

Interesting. I have a 135/5.6 Convertible Symmar that grew haze in both cells. I could unscrew one cell's retaining ring, the inner surfaces cleaned up well. The other cell was harder, in fact its still waiting. I have other 135s.

About cement. By the time these lenses were made Schneider had started using synthetic cements. If the hazing is between the elements an outer group -- a long soak in a solvent will separate them.

Leigh B, have you looked at it lens? Why do you think the problem is fungus?

210/5.6 Convertible Symmars aren't valuable lenses. At today's prices, replacing it with, say, a 210/5.6 Fujinon W wouldn't be a bad idea.

The biggest risk with taking one of these things apart is putting an inner element back facing in the wrong direction. I did this once with a 180/4.8 Ilex. Had to take it apart again ...

 

[removed account4]

I have a Schneider 210/370mm convertible lens. The front lens group has haze which has been getting worse since I started using the lens. I would like to clean the haze but it is between the elements. I can't get the front element ring off to get to the haze. Does anyone have any suggestions on how to loosen up the ring. I have tried using heat but it has not made a difference. Are there any compounds that I can use to loosen it that pose little risk to the glass? Thanks

good luck cleaning the lens !
if you poke around here, and hte large format site
you might find jim galli's recipe for washing his lens element cleaner
i think there is H2O2 but i can't remember how much or the dilution,
it seems to work wonders ...
nice lens btw, i have one that might have a little bit of "schneideritis"

 

[AgX]

The retainer rings of lens may have a clear thread locker applied at the factory and will not budge until the thread locker is dissolved.

My impression is that locking glues left traces that one can see in differennt shine near that slit between the threaded parts.

 

[shutterfinger]

Not always.

 

[Darkroom317]

Tried acetone with no luck. The ring is still stuck.

 

[shutterfinger]

According to A Lens Collectors Vade Mecum the front barrel is thin brass and is easily damaged/bent. Is there any deformation of the barrel/will a filter thread in easily?
Soft heat as described in post #7 not to exceed 300°F can be safely tried as can applying penetrating oil to the threads and letting sit 12 to 24 hours may be necessary.

I have two clean examples and will sell one.

 

[Darkroom317]

According to A Lens Collectors Vade Mecum the front barrel is thin brass and is easily damaged/bent. Is there any deformation of the barrel/will a filter thread in easily?
Soft heat as described in post #7 not to exceed 300°F can be safely tried as can applying penetrating oil to the threads and letting sit 12 to 24 hours may be necessary.

I have two clean examples and will sell one.

No deformation that I can tell. I've read about using a penetrating oil. What you you recommend? As far as replacement, if it comes to that, I'm leaning towards a newer lens.

 

[shutterfinger]

The Vade says the retainer ring can be very difficult to remove. I use Liquid Wrench Penetrating Oil. Once separated I wash every thing with 90% Isopropyl Alcohol.

As far as a replacement lens I have no suggestions.

 

[Dan Fromm]

Re replacement, it seems that the best modern values going are Fujinons. This site http://www.subclub.org/fujinon/ explains the versions. I'd go for a 210/5.6 NW (engraved "W" on the outside of the front cell's barrel, s/n on the rear cell, in Copal shutter). But these aren't intended to be convertible. The only 210 (or so) more modern than the convertible Symmar that's intended to be converted is the 215/4.8 Ilex Acugon, rear cell is 354/10. They're a little thin on the ground.

 

[paul ron]

have you tried using a rubber plug the size of the ring? ive got several plumbing test plugs in various sizes.

also overlooked... freezing a lens will often make removing rings easier.

 

[Darkroom317]

Re replacement, it seems that the best modern values going are Fujinons. This site http://www.subclub.org/fujinon/ explains the versions. I'd go for a 210/5.6 NW (engraved "W" on the outside of the front cell's barrel, s/n on the rear cell, in Copal shutter). But these aren't intended to be convertible. The only 210 (or so) more modern than the convertible Symmar that's intended to be converted is the 215/4.8 Ilex Acugon, rear cell is 354/10. They're a little thin on the ground.

The Fuji 210mm W is the lens I've been looking at. I bought the Schneider because I needed a 210mmI though it would be nice to have the longer focal at times. However, I've hardly used it at 370mm since I got it so being convertible is no longer a factor

 

[Darkroom317]

have you tried using a rubber plug the size of the ring? ive got several plumbing test plugs in various sizes.

also overlooked... freezing a lens will often make removing rings easier.

Tried freezing and it didn't work either.

 

[shutterfinger]

I would saturate the threads with nail polish remover and keep it wet for a few hours then try again.

Freezing has the same effect as soft heat. Soft heat expands then contracts on cooling breaking the bond between the ring and barrel, freezing contracts the expands as the lens warms up breaking the bond between the ring and barrel. Freezing potentially add moisture to the lens and soft heat does not.