Coating Lenses

[Ian Grant]

Yesterday I had a quote to coat a 135mm Eurynar lens, the minimum cost was $195 per surface, this lens has 8 air-glass surfaces so that's not even remotely practical. Maybe only the air-glass surfaces facing the light source actually need coating.

John Van Stelten from Focal Point was very helpful in his reply indicating that each surface wood need repolishing to remove oxidation etc, any cemented elements would need to be split, old cement removing etc. He also said it "We do this as a repair and it is far too expensive to coat an entire lens system"

Being rather more realistic I remembered coming across someone who had his old lens coated (he may have done it himself) at an opticians lab, using the coating process used for spectacles (glasses).

Has anyone tried this. A lens like the Eurynar would be ideal as the elements aren't cemented, and they suffer badly from low contrast due to this.

Is there a tame optical technician on APUG ?

Ian

 

[ic-racer]

Sounds like a cool project if you know an optician, though I suspect they outsource the coating. The glasses I have on now were coated, and they charged quit a bit for it.

Here is an overview of 'optician coating' and the machine you need:

Dead Link Removed

Dead Link Removed

 

[Mick Fagan]

Ian, this mob in Tasmania has been the duck's guts for odds and sods for years.

We (previous work) sent a lens that had been terribly rubbed on the front element after travelling for about 1,000 kilometres in a wooden box over corrugated dirt roads. It looked like throw away item. We sent it to this place and it came back with a new coating on the front element. They may have polished it as well, but it was far cheaper than anything else we considered by a long shot, plus it worked.

I believe at the time, they coated our lenses in their vacuum chamber coating thingy. Heavens knows what they have these days, but they are well known for doing all sorts of wonderful things around the world.

http://www.longmanoptical.com.au/index.html

You should check out the products page, scroll down to near the end and read about their optical coatings, there is an email click just there, so you can get a quote.

Worth a try!

Mick.

 

[Ian Grant]

Thanks Mick, email sent to them

Ian

 

[Ian Grant]

Longman Optical came back with an estimate and wow you're right Mick, the cost of coating is $180 AUS ($142 USD - £79 roughly) that's for all 8 surfaces. That assumes the elements are sent disassembled, otherwise there's an additional cost of $160 AUS.

This is for single layer MgF2 coating which they say is sufficient. This becomes a viable option at those prices.

Ian

 

[JPD]

Thanks guys for this thread. I also have a 135mm uncoated Eurynar that I will test some day, and maybe have it coated if I like the results. The elements are easily disassembled - just screw the lens mounts apart and out comes the glass.

Ian, I see that the also do reflective coatings, so remember to use the word "ANTI-" when you write the note that you send them with the lens elements.

 

[Ian Grant]

Longman Optical said they only offer single layer MgF2 coating, and as Mick says they regularly coat camera lenses. This seems to now be the only company offering an affordable option for lens coating now that Arax no longer offer a coating service.

Ian

 

[Mick Fagan]

Ian, if you do go ahead, I believe you will be pleasantly surprised at the difference and their service.

Mick.

 

[Ian Grant]

Mick I'll test the lens when I'm next in the UK, if it's sharp with good edge/corner coverage I'll get it coated and see how much difference it makes. Ole rates the Eurynar lens very highly and I guess it's similar in to the Goerz Celor in image quality.

Ian

 

[Paddy]

now that Arax no longer offer a coating service.

Ian

I'm sorry to hear that Arax is no longer offering their (re)coating service. I had a 270 G-Claron with dull outer surfaces redone by Arax, a couple of years ago. It came back pristine and Multi-coated!!!

 

[Denis P.]

I have also had a Summicron front element recoated by Arax.
Like others said, their service was impeccable - the lens came back coated better than when it left the Leitz factory back in 50-ies... i.e. multi-coated!

Alas, Arax does not offer such service any more.

The info about Longman Optical is a very welcome news indeed!

 

[Ian Grant]

Dead Link Removed in London also re-coat lenses but are much more expensive.

Ian

 

[David A. Goldfarb]

There is a company called Superflat that recoats lenses for the cine industry, but as I recall, you have to disassemble the lens and send them the elements.

 

[Mark Layne]

Just a personal opinion, but I feel the beauty of the Eurynar is the fact that it is not coated
Mark

 

[Ian Grant]

You may be right Mark, but I'll test it first. I've been shooting with an uncoated Tessar and want a slight increase in quality, the Eurynar is far easier to get coated should then give a contrast closer to a modern lens, also far less prone to flare.

I also have another uncoated Rodenstock 135mm lens so that leaves me options for that 30's rounded tone look.

Ian

 

[sun of sand]

Has anyone ever thought of contacting JML Optics? They've made good lenses themselves so seems like a quality place to try
I believe I read somewhere on their site their founder was an old Ilex guy

They have a coatings section and it appears to say MgF2 coating for a smaller diameter lens would be in the $25 per surface range
but I could be misreading that totally

http://www.jmloptical.com/level2/index.aspx?pagename=ProductInfo/antireflective_info.aspx

You can see their setup and process on a lens making Youtube video

 

[GeorgesGiralt]

Hi !
Seing this, and having tried to have re-coated a front lens damaged on cleaning, I thought it could be of some help.
Alas, an optic teacher I know said to me "Single layer MgF2 coating ? It is a circa 1935 technique. Not so good by today standard."
So, it could be good for an uncoated lens, but do not expect tremendeous results.... if I understand what this guy said to me.

 

[Ian Grant]

Georges, single layer coating can be excellent, modern methods have improved significantly since their first invention and early techniques.

Sure it's not going to be as good as Multi-coating on a modern lens but equally many companies say that multi-coating isn't particularly beneficial to older pre-war lenses anyway and doesn't give the improvements you expect and can take the edge of sharpness etc, and single coating is sufficient.

Ian

 

[JPD]

The difference between single- and multicoated lenses with six or eight surfaces is hardly noticable. Modern single coating can reduce the internal lens reflections by 90% or more.

 

[JPD]

I'm waiting for another Eurynar 4,5/13,5cm. Hopefully it's in better condition than the one I already have ("cleaning marks"). The Eurynar is easy to take apart, which is great if I decide to have the elements coated.

I'm also waiting for a Goerz Dogmar 6,3/135mm It should be good, as it is Goerz improved version of the Celor. Still a dialyt, but not as symmetric as the Celor.

 

[JPD]

Longman Optical came back with an estimate and wow you're right Mick, the cost of coating is $180 AUS ($142 USD - £79 roughly) that's for all 8 surfaces.

I got this estimate:

The best way to answer this is to send elements and I will quote.....but
because you are a fair distance away, on averages the cost is app. $40 each
surface + postage.
I must also mention that the coating is a single layer MgF2 coating and not
multi-coated.

That's $320. :confused:

 

[JPD]

Update: $200 for just cleaning and coating four elements.

 

[phfitz]

JPD,

"Update: $200 for just cleaning and coating four elements."

What diameter?

 

[DaveOttawa]

I got this estimate:

That's $320. :confused:

As it happens I have some experience with using and sourcing coated camera optics. A few observations: you get what you pay for to some extent, re-coating a camera lens involves a certain amount of labour then some time on fairly expensive equipment (vacuum coater) operated by a skilled (you hope) technician. Parts have to be cleaned rigourously before cleaning and probably inspected than packed afterwards. It all costs money.
Coating type: MgF may be fine for the inner surfaces that are not normally able to be touched but for the first surface you have to consider the coating durability. However good it is optically if it wipes off the first time you try and clean it that is no good. So ask any potential supplier if they are applying a hard coating and if so how they define "hard". I have definitely seen very soft MgF coatings - they will be partly removed by just one pass with a paper wipe.
There is really no optical downside to coating, it wll not affect sharpness as someone implied above - although disassembling the lens to coat and reassembling slightly off obviously could.

 

[JPD]

JPD,

"Update: $200 for just cleaning and coating four elements."

What diameter?

33mm or so.