Mamiya k/l 127mm repair, optical adhesive used

[Brusselsbased]

Dear community,

I own a mamiya 127mm K/L lens. The lens has a “foggy” rare lens doublet. Which I recently learned is quite common on this particular lens. Most listing on eBay rated at near mint/exc5 or even mint have this problem (which is for another discussion as rating of lenses especially by Japanese sellers over the years have degraded significantly.)

many people use these lenses with that condition as is, which is doable, and somewhat gives you a soft focus 127mm lens if you watch out for high contrast scenes, or during long exposure night photography you will get results somewhat similar to the look of cinestil 800t. Which I do not like (for my style the more sharp the image is the better, even for portraiture.)

after consulting with photo repair stores, optics labs, and even some of my scientist friends who work in the field of optics I learned that no one will take my oldy MF mamiya glass and take apart the doublet re-align and recement it. I was told that the price for the job is just many times higher than the price of the lens.

so here comes the fun part. I decided to do it myself. As I really have no use for a soft 127mm. Now the doublet is being soaked In methylene chloride and soon will be ready for re-cementing.

the question is does anyone know what kind of optical adhesive was used in mamiya k/l glass? I assume it’s a synthetic cement or UV cured epoxy adhesive as it did not look like Canadian balsam or something of older types adhesives. The most important question is does anyone know the refractive index of the used adhesive? So I can chose a replacement accordingly.

best regards,

mark

 

[David Buddenhagen]

Hi Mark,
I don't see replies to your question regarding adhesive type/refractive index. I recently bought a mamiya 127mm K/L lens and it too has rear element fog. I am tempted to try heating it to clear it, but am concerned that that trick only works with Canadian Balsam adhesive - Did you find out what adhesive the Mamiya used for the 127mm K/L lens? Have you had any luck removing fog from the one you own?

Kind regards
David

 

[Dave Krueger]

Dear community,

I own a mamiya 127mm K/L lens. The lens has a “foggy” rare lens doublet. Which I recently learned is quite common on this particular lens. Most listing on eBay rated at near mint/exc5 or even mint have this problem (which is for another discussion as rating of lenses especially by Japanese sellers over the years have degraded significantly.)

many people use these lenses with that condition as is, which is doable, and somewhat gives you a soft focus 127mm lens if you watch out for high contrast scenes, or during long exposure night photography you will get results somewhat similar to the look of cinestil 800t. Which I do not like (for my style the more sharp the image is the better, even for portraiture.)

after consulting with photo repair stores, optics labs, and even some of my scientist friends who work in the field of optics I learned that no one will take my oldy MF mamiya glass and take apart the doublet re-align and recement it. I was told that the price for the job is just many times higher than the price of the lens.

so here comes the fun part. I decided to do it myself. As I really have no use for a soft 127mm. Now the doublet is being soaked In methylene chloride and soon will be ready for re-cementing.

the question is does anyone know what kind of optical adhesive was used in mamiya k/l glass? I assume it’s a synthetic cement or UV cured epoxy adhesive as it did not look like Canadian balsam or something of older types adhesives. The most important question is does anyone know the refractive index of the used adhesive? So I can chose a replacement accordingly.

best regards,

mark

I will be watching this thread with great interest. I have a 127mm Mamiya-C lens with fog on both front and rear lens pairs. After trying to get someone to repair it, I used the heat method which made a very noticeable improvement, but not enough. That thread is here.

I also had the experience of buying a 127mm K/L lens from ebay that specifically described it as having no haze or fog. It had substantial haze, so I sent it back. At that point, my faith in getting another 127mm lens on ebay without any haze dropped to zero.

I would still love to fix my 127mm lens since the rest of my RB-67 equipment is in superb condition, but I got burned out and gave up. I don't have enough knowledge to offer any help, but I certainly hope you succeed with your attempt to fix it. If you do succeed, there are probably enough hazy Mamiya lenses out there where you could start a successful business doing it for other people. Me, for example.

Ah-ha! Brusselsbased, I just noticed that you already posted in my old thread back in February.

 

[shutterfinger]

https://www.edmundoptics.com/f/norland-optical-adhesives/11818/
I don't know what Mamiya used but I would go with #61.