Old lens polish and coat

[m. dowdall]

I have a Zeiss Protar VII "D" set in a barrel from the mid 1920’s. Just last night I won a 48cm and 41cm mounted in a Betax shutter. I think this set will be a good light weight combination for 8X10 (well light for 8X10). I’ve been using the ‘D’ set for about two years now but find the contrast to be low on bright days. I use a compendium shade. The cells have a number of cleaning marks on them. Nothing deep, just haze and swirls you can see when held to light at certain angles or shine a flash light though them.

I also have another Protar set that covers 4X5 in a shutter. The cells are clear, no haze or swirls. The images are sharp and contrasty and I’d love to have the longer lengths look the same.

Does anyone know of lenses of this age being polished and coated? What where the results? I’ve emailed Focalpoint for a quote.

Thanks

Michael

 

[David A. Goldfarb]

Burke and James and some other companies used to do it routinely. I have an old Schneider Xenar with a B&J aftermarket coating, and the results are good.

 

[JG Motamedi]

It is going to be very expensive. John Van Stelton at FocalPoint does great work, but he isn't cheap. If I recall correctly you are going pay $175 for each surface coated. However, he will also have to decement, polish, and recement each of the groups in order to coat them; this is very expensive for the Protar since there are four elements, about $300 per group. So you are looking at roughly $1300 for redoing two elements. Is it worth it?

There is a firm in England, optil.co.uk, whose prices are lower, however they don't seem reliable. I sent a lens for repolishing to them about 6 months ago, and they still haven't done the work. I wouldn't recommend them.

 

[David A. Goldfarb]

There's another company called "Superflat," which does a lot of this for the movie industry. I've heard good things about them, but you have to disassemble the lens yourself and send them the elements, if I remember correctly.

 

[Paul Howell]

I have an old Burke and James 210 for my even older crown, not a great lens but usable. I did not want to spend the money to have it repolished and coated by one the commerical concerns. So I found a local optical (eye glasses) shop that polished and coated the elements for under a $100. They used the standard UV and a light gray tint for glasses. I do not use this lens for any color work, but for B&W it has better contrast and the polishing seems to have improved the overall sharpness. I plan on trying some E 6 film in it to see what would happen with color.

Paul

 

[m. dowdall]

Thank every one for your replies. I got a speedy reply from focalpoint, though I'm sure they would do a great job, they’re price was to high for my needs. To polish and coat, $195 per surface (6 cells x 2 sides x $195 = $2340) ouch! That doesn’t include separating and recementing. I spent some time searching the internet and made some phone calls and came up with two quotes to have the lenses coated $200 to $300 for all 6 cells. I would have to polish them, separate and recement them. One of the quotes would use a low temperature process for less chance of breakage. I was unable to find “Superflat”. The two links I found are:

http://www.accucoatinc.com/index.htm

http://www.thinfilmcoating.com/

Well I’m going to have to think about this for a while. It might be a good idea to try polishing, separating and cementing a lens of lesser value before I try this one on the good lens set.

Michael

 

[medform-norm]

tip? Maybe?

HI Michael,

have you thought about finding an instrument making school (sorry, I'm at a loss for a better translation), where they have an optics department? You might get lucky there. We found one in Holland and asked if they could help us with a hazy lens. We talked to the optics teacher and he said one of the students could do the polishing job as part of their training -and they get trained well, I can tell you that! they are the elite corps of this school - and we could talk about coating later.

As it turned out, not the glass itself, but only the existing lens coat was hazy due to overexcessive cleaning. One of the students removed this coating in exchange for a large cake for the whole class. Costs: 10$. We decided not to go for recoating the lens, since the camera wasn't worth it, but they could have done that too and I bet it would not have cost as much as a commercial company would have to charge. The polishing was extremely well done, so I expect they would have done the coating likewise.

Of course, one can never become a school's regular customer, as the students need diversity in their training, but it was fine for the odd job. The optics teacher said they would allow for that now and then, if it fitted in with the curriculum. Might this be a useful suggestion? Or are you afraid to entrust your lens to a student?

Good luck,
medform-norm

PS On second thought, I think we should all do this now and then to impress these schools and their students with our need for well trained optics experts. Most students of this particular school would go on to find jobs in extremely high-tech labs of universities - and might never think of a career in lens work if we would not remind them of our existence...

 

[m. dowdall]

Tip

Thanks medform-norm I'll look into that.