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View Full Version : Aero Ektar with spots on the glass, can it be saved?



thicktheo
16-Dec-2011, 11:03
So I got this lens from a friend who exposed it to too much light in order to clear the yellowish tint... the yellowish tint did go away but some spots appeared on the glass elements - in the front glass element they look like "blooming" and in the back glass element they look like stains.

See the attached photos.

My questions are:
1) how will these spots affect my image? I haven't tried the lens yet.
2) are they removable and if so, how do I remove them? If I take them to a local lens repairman, can he do anything?

I would be thankful on any replies on this matter... it's a nice lens and it is a shame to throw it away.

Kevin Crisp
16-Dec-2011, 12:15
Looks like classic separation of post-balsam 1950's lens cement. Possibly the light source used to clear the tea stain from radioactivity was too hot?

Yes, it can be cured, but you have to take the affected elements out, separate them, and reglue them.

thicktheo
16-Dec-2011, 12:21
Looks like classic separation of post-balsam 1950's lens cement. Possibly the light source used to clear the tea stain from radioactivity was too hot?

Yeah, from what I know, the light source was too hot... shame.



Yes, it can be cured, but you have to take the affected elements out, separate them, and reglue them.

I am not at all familiar with this process - I mean, I can open up a lens, no problem, but separate glass elements, reglue them, etc, that's a feat far away from my abilities, mainly because I don't have the spare time (or spare work area) to do it. Is it an easy job for a professional lens repairman, or they don't meddle in such things? I've got a couple of guys here in Athens who repair old cameras, align lenses, etc.

In any case, how will this balsam separation affect the resulting image? Lowered contrast? Flare?

Kevin Crisp
16-Dec-2011, 12:27
You can learn to do it yourself, but there is a learning curve. If you can unscrew a retainer or whatever and email me a photo of the element with the separations, I can try to walk you through it. Hopefully the diameters of the two pieces of glass that are glued together are the same; otherwise, it complicates things.

There are UV lights that CF bulbs that eliminate the potential for this since they barely get the lens warm.

thicktheo
16-Dec-2011, 12:28
What materials do I need in order to separate the glass elements and then glue them back together?

Łukasz Owsianka
16-Dec-2011, 12:38
You have to take the cemented lenses and put them into cold wather and slowly heat to max 80 degree celsius (lenses musn't touch the bottom of the pot) Let them cool slowly - you have to repeat it several times. Canadian balm should dissolve in to the water. Then recement the lenses. If you do it to fast It will destroy the lenses... I done it one time with aplanat lenses...

Canadian balm is easy to buy

Kevin Crisp
16-Dec-2011, 12:40
There have been recent suggestions that boiling water will do it, with the temperature raised very slowly. I haven't tried that. I have used soaking in solvent to do it, but that doesn't do it very quickly. (On the other hand, there is no chance of breaking the glass.)

You need to then clean the glass off with very clean acetone, reglue with UV curing lens cement, and then set it with UV light. Summers Optical has lots of information on this.

John Schneider
16-Dec-2011, 12:48
There is an old link at SK Grimes about recementing. That plus the info at Summers Optical should be plenty, supplemented by the info here. I used heat to soften the balsam to allow the elements to be separated, which is another method.

Kevin Crisp
16-Dec-2011, 12:53
This isn't balsam separation though, from the looks of it.

thicktheo
16-Dec-2011, 12:58
I will try the lens first against a different, clean, Aero Ektar I borrowed in order to see how much this cementing degradation (whatever it is) affects the final image. Hopefully I'll do it tomorrow, maybe some studio still life shots and some kind of landscape. I'll let you know about the results.

Frank Petronio
16-Dec-2011, 12:59
Why not shoot with it and try it? They aren't used for high resolution and detail as much as artistic effect, so maybe it will look fine as-is?

Louis Pacilla
16-Dec-2011, 13:02
I will try the lens first against a different, clean, Aero Ektar I borrowed in order to see how much this cementing degradation (whatever it is) affects the final image. Hopefully I'll do it tomorrow, maybe some studio still life shots and some kind of landscape. I'll let you know about the results.

If you got the lens for a fantastic price I would just shoot it like it is. Shield the front cell from stray light and I will bet you wont be able to tell the difference between the spotted Aero Ektar from the clear one.

thicktheo
16-Dec-2011, 13:10
If you got the lens for a fantastic price I would just shoot it like it is. Shield the front cell from stray light and I will bet you wont be able to tell the difference between the spotted Aero Ektar from the clear one.

Got it for less than 100, so yes, it is a fantastic price (at least in the European market).

I'm gonna try it out tomorrow, then, and see what happens. Fomapan 400 should fit the bill.

Steven Tribe
16-Dec-2011, 13:19
I doubt the results will be very good.
It is the rear cell that goes yellow/brown and these cement spots look very opaque to me.

Paul Fitzgerald
16-Dec-2011, 19:26
Try it out the way it is and see if it will work for you.

Aero-Ektar does not use balsam, it was one of the first lenses to use synthetic adhesives. Heat will not help you, they were military grade, expected to go far 140* on the runway to -40* at altitude within minutes.

The only way you will get it apart is to soak it in acetone or methylene chloride (paint stripper) and it will take weeks for the vapors to reach through that diameter of glass. Much easier to have a pro do it BUT it will cost. Check the link below.

Norland Optical Adhesive #61 (http://www.norlandprod.com/adhesives/NOA%2061.html)

jcoldslabs
18-Dec-2011, 03:33
I have a good friend whose Aero Ektar has a large abrasion/scratch probably 1/4" by 1" across the center of the front element. When he bought it (he got a deal) I was convinced he would see image degradation as a result of the damaged optics, but I have never seen a difference between the results he gets with his lens and my nearly mint one. My guess is you'll be fine.

We both shoot ours wide open, of course, so that probably helps mask any flaws.

thicktheo
18-Dec-2011, 04:51
I tested it yesterday, sadly no clear sun so I couldn't test the flare, etc. I did shoot some against-the-cloudy-sun frames but I have to develop them.

I also took the two attached polaroid shots, the pigeons are wide open at f2.5 (1/500) and the portrait is at ~f4.5 (1/125), sun hidden behind the clouds in both cases.

As far as I'm concerned, the lens performs greatly on no-direct-light situations. I'm keeping it as it is.

eddie
18-Dec-2011, 07:04
This isn't balsam separation though, from the looks of it.

yes it does. especially the last image.

just shoot with it. you will not see anything. playing with it may result in a broken or useless lens.....or if you pay some one a very expensive lens.

Frank Petronio
18-Dec-2011, 07:25
It's like trying to fix a Lens Baby!