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Lens repair/repolishing/coating in Germany
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PostPosted: Fri Nov 23, 2018 8:48 am    Post subject: Lens repair/repolishing/coating in Germany Reply with quote

https://www.pstechnik.de/services/lens-service/polishing-recoating/


PostPosted: Mon Apr 22, 2019 1:01 am    Post subject: Re: Lens repair/repolishing/coating in Germany Reply with quote

Thanks for sharing!

I have requested a quote for the coating on the camera facing side of the rear doublet - Kilfitt Makro-Kilar 1:2.8/90.


PostPosted: Fri Apr 26, 2019 12:42 pm    Post subject: Reply with quote

Quote:
Lenses manufactured before 1970 typically had a single layer coating. Lenses manufactured later have multi-layer coating.


Well, that isn't quite accurate - and I seriously question the claim they can replicate an original coating. Further, they will not cover any damage or loss to the lens elements due to their own fault. Still, useful to know providers of specialist services, I've also asked for a quote but for recementing doublets.


PostPosted: Sun Apr 28, 2019 2:33 pm    Post subject: Reply with quote

Teemō wrote:
Quote:
Lenses manufactured before 1970 typically had a single layer coating. Lenses manufactured later have multi-layer coating.


Well, that isn't quite accurate - and I seriously question the claim they can replicate an original coating. Further, they will not cover any damage or loss to the lens elements due to their own fault. Still, useful to know providers of specialist services, I've also asked for a quote but for recementing doublets.


I agree with your claims, but what's the harm is asking. Twisted Evil

If the quote is fair, then make it a low risk of loss endeavor. I paid less than $200 bucks for the lens I am seeking repair, and would be willing to pay no more than 50% of that for this experiment.

I have seen a Patent that uses alternative Acid / Alkali baths in order to remove a Magnesium coating.

My ambition is that a lab could perform this task instead of having to lap, polish, re-figure a element, shim the lens to bring it back to acceptable focus.

As well, I have read that some older single coatings were hand painted onto the element.

Please follow up if you hear back from them.

Thanks


PostPosted: Sun Apr 28, 2019 5:07 pm    Post subject: Reply with quote

Update!

They did reply in a timely manner with a quote next day, but it filtered into my junk folder.

I think the prices are fair considering the task. The quote was a la carte or line item. The cost appears to be based on the surface area involved, which is considerate. Prices are EU, obviously.

Regards


PostPosted: Mon Apr 29, 2019 6:13 am    Post subject: Reply with quote

Blazer0ne wrote:
Update!

They did reply in a timely manner with a quote next day, but it filtered into my junk folder.

I think the prices are fair considering the task. The quote was a la carte or line item. The cost appears to be based on the surface area involved, which is considerate. Prices are EU, obviously.

Regards


how much was it?


PostPosted: Mon Apr 29, 2019 1:35 pm    Post subject: Reply with quote

Blazer0ne wrote:


I have seen a Patent that uses alternative Acid / Alkali baths in order to remove a Magnesium coating.

My ambition is that a lab could perform this task instead of having to lap, polish, re-figure a element, shim the lens to bring it back to acceptable focus.

As well, I have read that some older single coatings were hand painted onto the element.

Please follow up if you hear back from them.

Thanks


I've certainly never read of hand-painted coatings. It should be an industrial process because the efficiency and benefit of the coating depends on the precise thickness of one layer compared to another. The risk to a new coating on a modern lens is that it does not play nicely with the original coatings, either on the same element or a different one, since the rays are traced at every interface. A coating is not just one homogeneous "multi-coating", it is made up of many single layers.

I did get a reply email. They said they do not service Voigtlander lenses (what I inquired about) so they would only re-cement a doublet if the elements were removed and sent to them. The reason they do not insure their work is because they do not know what cement is used on a lens in production and there is a risk the elements crack. To that end, I guess they will not warranty that service either.
As far as I know. if it is UV-cement, there are few solvents that will work (and those that did may be banned due to their toxicity). I'm not aware of other cement materials between UV-cement and Canada balsam, but whatever Cosina/Voigtlander uses can be separated.

Unfortunately, the price is 400 Euro to separate and re-cement a doublet, so this seems like a service oriented to commercial equipment as there are few photographic lenses on which the cost could be justified.


PostPosted: Mon Apr 29, 2019 4:54 pm    Post subject: Reply with quote

Thanks for the feedback.

I think it is good to get it out in the open: the total amount of effort and risk involved with such a task.

I believe this is why such a service is typically niche to cinema. A production or lens rental studio can realize ROI.

I also queried about the the potential consequences, and it appears that part of the service agreement is to limit the liability of the service provider. This is smart of them, and I believe anyone else providing such a service would do the same.

In most cases, to render this service would mean, the lens was already written off as a loss. The investment into the service is a gamble to recover that loss. Obviously, it doesn't make sense if you can easily replace the lens or group at a similar cost with another copy.

What I learned is that they will attempt to minimize the potential for catastrophe. For example, a cemented doublet would have to be separated before polishing and re-coat. Even if the coating damage is on the non-glued side. This is to reduce any risk of breakage.

I would also think that to have multiple single elements reconditioned would likely lower the per unit cost at the point of re-coating.


Thank You Dog


Last edited by Blazer0ne on Mon Apr 29, 2019 4:57 pm; edited 1 time in total


PostPosted: Mon Apr 29, 2019 4:56 pm    Post subject: Reply with quote

Teemō wrote:
I've certainly never read of hand-painted coatings.


It may be called coagulated coating as opposed to vacuum chamber deposition method.


PostPosted: Wed May 01, 2019 2:36 pm    Post subject: Reply with quote

Blazer0ne wrote:
Teemō wrote:
I've certainly never read of hand-painted coatings.


It may be called coagulated coating as opposed to vacuum chamber deposition method.


I cannot find anything about that term. The coating thickness should be about 1/4 of the target wavelength, which is impossible to paint by hand. The only other possibility may be some dunk/dip method that leaves a thin-film, or perhaps another chemical can painted atop to react and produce an oxide layer.


PostPosted: Wed May 01, 2019 2:52 pm    Post subject: Reply with quote

Teemō wrote:
Blazer0ne wrote:
Teemō wrote:
I've certainly never read of hand-painted coatings.


It may be called coagulated coating as opposed to vacuum chamber deposition method.


I cannot find anything about that term. The coating thickness should be about 1/4 of the target wavelength, which is impossible to paint by hand. The only other possibility may be some dunk/dip method that leaves a thin-film, or perhaps another chemical can painted atop to react and produce an oxide layer.



I don't have much to go by. Here is the source referring to a lens for a Kodak-Retina.

https://www.dantestella.com/technical/retina.html


Quote:

The one thing about the Schneider lenses (which appear to be vacuum-coated, rather than coagulation-coated) is that they sometimes develop tiny "stars" in the front element coating. This has no effect.


PostPosted: Wed May 01, 2019 2:54 pm    Post subject: Reply with quote

I have moved my personal lens issue to a new thread, and will gladly accept any comments that way.

http://forum.mflenses.com/makro-kilar-90mm-f2-8-coating-damage-what-is-the-impact-t80515.html


Like Dog


PostPosted: Wed May 01, 2019 3:21 pm    Post subject: Reply with quote

kansalliskala wrote:
How much was it?


PM sent Arrow


PostPosted: Thu May 02, 2019 8:16 am    Post subject: Reply with quote

Blazer0ne wrote:
Teemō wrote:
Blazer0ne wrote:
Teemō wrote:
I've certainly never read of hand-painted coatings.


It may be called coagulated coating as opposed to vacuum chamber deposition method.


I cannot find anything about that term. The coating thickness should be about 1/4 of the target wavelength, which is impossible to paint by hand. The only other possibility may be some dunk/dip method that leaves a thin-film, or perhaps another chemical can painted atop to react and produce an oxide layer.



I don't have much to go by. Here is the source referring to a lens for a Kodak-Retina.

https://www.dantestella.com/technical/retina.html


Quote:

The one thing about the Schneider lenses (which appear to be vacuum-coated, rather than coagulation-coated) is that they sometimes develop tiny "stars" in the front element coating. This has no effect.


Okay, interesting! Although I cannot find any other references for that, there is an industrial process for coating of aerosol nanoparticles by vapour to preserve them and make them more pliable to surface application. through coagulation and sintering. This is not an optical process, although perhaps it was tried and written somewhere in early Schenider/Kodak literature. I can certainly see how a lens might coated by 'airbrush'. It would be interesting to see what are the 'stars' referred to by Dante. Of course, I'm just speculating about what they meant by "coagulation".


PostPosted: Thu May 02, 2019 1:55 pm    Post subject: Reply with quote

Blazer0ne wrote:
kansalliskala wrote:
How much was it?


PM sent Arrow



Aw, come on! Please share!


PostPosted: Mon May 06, 2019 12:11 pm    Post subject: Reply with quote

Teemō wrote:
Blazer0ne wrote:




As well, I have read that some older single coatings were hand painted onto the element.


...



I've certainly never read of hand-painted coatings. ...



Dennis Taylor of Cooke Triplet fame was hand painting coatings around the turn of the 20th C. He patented the process in 1904, but he couldn't get it to convert to mass production, so we had to wait another 30 years or so.


I picked the above up from a blog by Roger Cicala. Blogs are not the best way to glean facts I'd agree, but he provides a list of his reference material at the bottom of the page.

https://www.lensrentals.com/blog/2011/01/cooking-with-glass/


PostPosted: Mon May 06, 2019 12:59 pm    Post subject: Reply with quote

visualopsins wrote:
Blazer0ne wrote:
kansalliskala wrote:
How much was it?


PM sent Arrow



Aw, come on! Please share!


I once asked for a quote from people who briefly advertised here their services for redoing separated elements. My recollection is that for a 1" doublet the cost was on the order $75-100. I was not really surprised.