Elmar 50/2.8 - removing damaged internal coating?

[IloveTLRs]

I have read about removing coating on this board, but I would like to ask about this lens ..

The Elmar 50/2.8 is known for being hazy/foggy but I picked up a very cheap example the other day. A camera shop told me that the coating had deteriorated and it could be cleaned and re-coated for not too much money. I have no need for a soft focus lens so I am looking to have it cleaned.

The source of the problem is on the rear of the front element. Under a loupe the surface appears to be pitted with tiny holes. Is this the coating coming off? A swab with a Q-tip did nothing, obviously: the "haze" remains.

Is the only option a repolishing? I thought I would turn my inquiry over to the lens masters on this board. Any help or advice is welcome.

 

[sangetsu]

I have removed the internal coating on a few old Canon and Leica lenses. The process is simple enough, but it can be a little tedious. First, I dampen a cotton swab with a bit of lens cleaning solution, then I add a bit of toothpaste. Then I begin to polish away the coating using a circular motion. Depending on the type of coating, it can take 10 minutes to an hour to polish it all off. The toothpaste is abrasive enough to remove the haze, but does not harm the glass. I have saved some pretty rotten-looking lenses using this method.

 

[summicron1]

i had this problem with this same lens -- the inner rear element does not need cleaning, it has been etched by outgassing from the grease in the lens. Sherry Krauter charged me $175 to replace the element and complained that that particular lens is hard to service.

lens now like new, sherry still complaining. Try DAG as well, and perhaps even Leica.

 

[Gerald C Koch]

Toothpaste is too abrasive and may damage the lens. Special compounds are used for lens polishing. Check sites that are devoted to telescope making. If you value the lens then have it repaired professionally.

 

[georg16nik]

I have successfully removed coating from Leitz Summitar 1950 with Hydrogen peroxide 3%.
Elmar 50/2.8 coating might be different thou.

 

[IloveTLRs]

Thank you everyone, for taking the time to reply. I have attached an image, which shows the rear surface of the front element in question.

 

[E. von Hoegh]

View attachment 59393

Thank you everyone, for taking the time to reply. I have attached an image, which shows the rear surface of the front element in question.

Looks like someone already did the toothpaste treatment on that one.

 

[IloveTLRs]

It looks like polishing is out because the element is quite thin. Short of replacing the front element, I now have an expensive Leitz paperweight.

 

[georg16nik]

It looks like polishing is out because the element is quite thin. Short of replacing the front element, I now have an expensive Leitz paperweight.

Did You tried anything on it?
The shot above is before or after intervention?

 

[ic-racer]

Sometimes that stuff wipes off easily.

 

[IloveTLRs]

This is after, and there was no change at all (though I only tried briefly)

 

[John Koehrer]

I have removed the internal coating on a few old Canon and Leica lenses. The process is simple enough, but it can be a little tedious. First, I dampen a cotton swab with a bit of lens cleaning solution, then I add a bit of toothpaste. Then I begin to polish away the coating using a circular motion. Depending on the type of coating, it can take 10 minutes to an hour to polish it all off. The toothpaste is abrasive enough to remove the haze, but does not harm the glass. I have saved some pretty rotten-looking lenses using this method.

I've used this method on several lenses with no observable change in lens quality(flare maybe?). Latest one is a 100mm V-Elmar.
The element is NOT too thin for this treatment, if you're using toothpaste. I use a tiny tube of Colgates I've had for at least 20 yrs. I just use my dainty index finger for the polishing bit and common lens cleaner for the last cleaning.