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View Full Version : 360 Symmar f/5.6 in Compound IV 10/2 Rear Element Removal



Jerry Bodine
26-Jan-2014, 11:35
The rear element has some minor "haze" and I tried to remove to try to clean it up. Reasonable force to unscrew was unsuccessful. It's a Sinar select lens factory mounted on a Sinar board purchased new, and I really enjoy its results. Had CLA by Flutot, Carol asked if she should try to remove it and I said no thanks; probably should have let her try. Anyone try to do this?

Randy Moe
26-Jan-2014, 12:17
I have the same problem.


The rear element has some minor "haze" and I tried to remove to try to clean it up. Reasonable force to unscrew was unsuccessful. It's a Sinar select lens factory mounted on a Sinar board purchased new, and I really enjoy its results. Had CLA by Flutot, Carol asked if she should try to remove it and I said no thanks; probably should have let her try. Anyone try to do this?

Jon Shiu
26-Jan-2014, 17:04
You can make two semi-circular wooden pieces to clamp onto the rear element that have a long handle to get leverage.

Jon

Jerry Bodine
26-Jan-2014, 17:21
Ok Jon, I'll give it a try since you imply that the rear element is actually threaded into the shutter and it's just a matter of "breaking" the friction loose (rather than breaking the element).

Randy Moe
26-Jan-2014, 17:28
I see, you cannot unscrew the rear from the shutter, I can do that, but my problem is the inner surfaces.

Good luck.


Ok Jon, I'll give it a try since you imply that the rear element is actually threaded into the shutter and it's just a matter of "breaking" the friction loose (rather than breaking the element).

Jerry Bodine
26-Jan-2014, 17:35
Randy, what do you mean by "the inner surfaces"? Internal lens surfaces that are "hazy"?

Jon Shiu
26-Jan-2014, 17:41
Or perhaps just use a rubber jar opener to grip?

Jon

Randy Moe
26-Jan-2014, 17:58
There are air gaps inside the rear element.

http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/symmar/


Randy, what do you mean by "the inner surfaces"? Internal lens surfaces that are "hazy"?

sanking
26-Jan-2014, 17:58
I see, you cannot unscrew the rear from the shutter, I can do that, but my problem is the inner surfaces.

Good luck.

That may be fungus. Exposure to a good dose of UV light will probably kill it.

Sandy

Randy Moe
26-Jan-2014, 18:02
Did not know that, thanks Sandy!



That may be fungus. Exposure to a good dose of UV light will probably kill it.

Sandy

sanking
26-Jan-2014, 18:25
Did not know that, thanks Sandy!

If the haze is in fact fungus the exposure to UV light will not erase the damage already done, but it may prevent it from getting worse. But if fungus, removing and cleaning the element would not help either, as the fungus etches the glass with its secretions. Really nasty stuff.

I had a nightmare once in which fungus spread over all my lenses. Fortunately I have a UV plateburner so I lined them all up under the continuous wave xenon and give them all four blasts of 600 units each. That did not help much in real life because it was only a nightmare, but I still feel better about it.

Sandy

Randy Moe
26-Jan-2014, 18:48
I was hoping it helped! Mine is fungus and if I can stop it, I can live with it.

Thanks again.



If the haze is in fact fungus the exposure to UV light will not erase the damage already done, but it may prevent it from getting worse. But if fungus, removing and cleaning the element would not help either, as the fungus etches the glass with its secretions. Really nasty stuff.

I had a nightmare once in which fungus spread over all my lenses. Fortunately I have a UV plateburner so I lined them all up under the continuous wave xenon and give them all four blasts of 600 units each. That did not help much in real life because it was only a nightmare, but I still feel better about it.

Sandy

Jerry Bodine
26-Jan-2014, 22:21
Did not know that, thanks Sandy!

Sandy, I don't know if my haze is fungus but I don't suppose it could hurt to try the UV treatment if the stuff is internal to the rear element. Any recommendations for UV sources and dosage? I'm not confident that "black light bulbs" are effective for this purpose.

sanking
27-Jan-2014, 17:15
Sandy, I don't know if my haze is fungus but I don't suppose it could hurt to try the UV treatment if the stuff is internal to the rear element. Any recommendations for UV sources and dosage? I'm not confident that "black light bulbs" are effective for this purpose.

Best light would be UVC light source, and a fairly long dose. Glass itself blocks a lot of UV radiation below about 350 nm, exactly how much would depend on the lens. UVB, which is available in compact fluorescent tubes, might also kill the fungus.

Fungus can spread so if you have a lens with a bad case of it you should isolate it from your other lenses.

Sandy

Randy Moe
27-Jan-2014, 17:52
Gad, spreading fungus, I have work to do tonight. Get that bad apple into isolation.


Best light would be UVC light source, and a fairly long dose. Glass itself blocks a lot of UV radiation below about 350 nm, exactly how much would depend on the lens. UVB, which is available in compact fluorescent tubes, might also kill the fungus.

Fungus can spread so if you have a lens with a bad case of it you should isolate it from your other lenses.

Sandy

Jerry Bodine
27-Jan-2014, 20:14
Gad, spreading fungus, I have work to do tonight. Get that bad apple into isolation.

I've quarantined mine already until I can get some UV into it. Been doing some online research for the right bulb + health safety issues. Must be careful with that kind of radiation, particularly vision, after my cataract surgery.

Randy Moe
27-Jan-2014, 20:26
I'm going to set up a CFL BLB in a Kodak Beehive and aim it closely at the offender. Most likely run it 24/7 for a while.

I suppose it will be impossible to determine progress or fungus death...



I've quarantined mine already until I can get some UV into it. Been doing some online research for the right bulb + health safety issues. Must be careful with that kind of radiation, particularly vision, after my cataract surgery.

Jerry Bodine
28-Jan-2014, 17:38
Well, I did manage to remove the rear element and found the haze is definitely internal. I'm now wondering if I should attempt disassembling the rear element (I know - GASP) to try to get at the haze to see if it will clean up. The haze looks like lots of little tan-colored specks with a relatively clear area around the edge of the optic about 3/16" wide. I don't know what fungus looks like. Also don't know what cement deterioration looks like. Probably safer to do the UVB dose first.

sanking
28-Jan-2014, 17:43
Well, I did manage to remove the rear element and found the haze is definitely internal. I'm now wondering if I should attempt disassembling the rear element (I know - GASP) to try to get at the haze to see if it will clean up. The haze looks like lots of little tan-colored specks with a relatively clear area around the edge of the optic about 3/16" wide. I don't know what fungus looks like. Also don't know what cement deterioration looks like. Probably safer to do the UVB dose first.

This page may help.
http://www.kenrockwell.com/tech/flashlight-test.htm

Sandy

Jerry Bodine
28-Jan-2014, 22:43
Thanks for the link, Sandy. It may help ID the haze before I take further action.

Nathan Potter
29-Jan-2014, 07:29
Look closely at the haze using a loupe, if possible. Fungus should show some dendritic growth patterns. Tan colored specks might suggest separation in the adhesive between the elements rather than fungus. If adhesive failure the only option might be to remove the glass elements and re-cement.

Re-cementing is not trivial but is possible by a careful worker. Look for a couple of posts here on various techniques especially jigging and heating while disassembling and re-assembling.

Nate Potter, Austin TX.

Jerry Bodine
31-Jan-2014, 22:42
Well, after searching all the threads I could find on fungus, haze, etc. and reviewing Sandy's link, I've concluded my problem is definitely not fungus and is likely a mild case of separation. It seems benign enough that I plan to continue using the lens, just avoiding backlighted situations. I'm not willing to risk damaging the lens by attempting to re-cement it myself. If it gets worse with age, I MAY look into having it re-cemented professionally, but I suspect the cost of that option may be a strong deterrent. However, I AM grateful for all your help. It was much appreciated.