Coating Lenses

Discussion in 'Large Format Cameras and Accessories' started by Ian Grant, Sep 13, 2008.

  1. Ian Grant

    Ian Grant Subscriber

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    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
     
  2. ic-racer

    ic-racer Member

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  3. Mick Fagan

    Mick Fagan Subscriber

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    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.
     
  4. Ian Grant

    Ian Grant Subscriber

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    Thanks Mick, email sent to them :D

    Ian
     
  5. Ian Grant

    Ian Grant Subscriber

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    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
     
  6. JPD

    JPD Member

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    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. :D
     
  7. Ian Grant

    Ian Grant Subscriber

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    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
     
  8. Mick Fagan

    Mick Fagan Subscriber

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

    Mick.
     
  9. Ian Grant

    Ian Grant Subscriber

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    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
     
  10. Paddy

    Paddy Member

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    I'm sorry to hear that Arax is no longer offering their (re)coating service. :sad: 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!!!
     
  11. Denis P.

    Denis P. Member

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    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!
     
  12. Ian Grant

    Ian Grant Subscriber

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    Balham Optical in London also re-coat lenses but are much more expensive.

    Ian
     
  13. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    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.
     
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  15. Mark Layne

    Mark Layne Member

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

    Ian Grant Subscriber

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    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
     
  17. sun of sand

    sun of sand Member

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    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
     
  18. GeorgesGiralt

    GeorgesGiralt Member

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    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.
     
  19. Ian Grant

    Ian Grant Subscriber

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    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
     
  20. JPD

    JPD Member

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    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.
     
  21. JPD

    JPD Member

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    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.
     
  22. JPD

    JPD Member

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    I got this estimate:
    That's $320. :confused:
     
  23. JPD

    JPD Member

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

    phfitz Member

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    JPD,

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

    What diameter?
     
  25. DaveOttawa

    DaveOttawa Member

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    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.
     
  26. JPD

    JPD Member

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    33mm or so.