Planning to send my Mamiya lens in for haze removal

[Dave Krueger]

I have a Mamiya-Sekor C 127mm f3.8 lens for an RB-67 Pro-s that has haze/fog on the inner elements. I bought the lens new back in the late 80s and it has been very well taken care of and functions fine in other regards.

I've been contacting camera repair shops and looking on ebay for a replacement lens. All the similar lenses on ebay are "From Japan" and are listed as EXC ++++++ or N.MINT even though the description on some of them say they have haze, so my trust factor is pretty low on getting a used lens in good condition.

So, I'd like to have my lens fixed. Basically, I would like to have the lens CLA'd and the haze removed. I got a reasonable estimate from Midwest Camera Repair in Michigan, but I thought I'd check here to see if anyone has had experience with them, good or bad, before sending the lens to them.

 

[shutterfinger]

Have you considered doing it yourself?
This Mamiya service manual https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Lenses-Service.pdf should cover your lens. LE103 C on pdf page 58 should be the correct diagram.
It has an element, air space, cemented pair, shutter/aperture blades, cemented pair. The element and pairs unscrew from the shutter and barrel.
Your haze may be cement failure in one of the pairs. Sometimes heat such as the pair submerged boiling water or heated in a oven to 300°F will clear the cement haze.
P.S.
I haven't dealt with Midwest Camera in about 20 years. They had a very good reputation at that time and likely still do.

 

[Mike Lopez]

Some of those Japanese eBay descriptions are hilarious. Seemingly everything is at least excellent with a minimum of 3 pluses. Good luck with your situation.

 

[Dennis-B]

...
P.S.
I haven't dealt with Midwest Camera in about 20 years. They had a very good reputation at that time and likely still do.

I've dealt with them recently, and they still do a fantastic job. I've had a couple of Ilex shutters repaired and timed, as well as some other more mundane work, and they are great folks to work with.

 

[Dave Krueger]

shutterfinger, thanks for the link to the repair info. I'm not sure I'd trust myself to do it without screwing something up, although I gather that self-repair is not uncommon.

I am assuming the haze is from shutter lubricants migrating to the elements, so I'm hoping the haze is on lens surfaces facing the shutter. But, I am a total novice, so that could be complete nonsense. I'm hoping it's not a cement problem. Assuming it is, are repair shops able to separate and re-glue the lens elements or is heat treating them the only solution?

In any case, I will review the youtube videos and see if I can get the tools for a self repair. There's a guy on youtube who cleans the inner elements with nail polish remover with acetone. Is that the way to go? Seems like acetone would damage or remove lens coatings.

Have you considered doing it yourself?
This Mamiya service manual https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Lenses-Service.pdf should cover your lens. LE103 C on pdf page 58 should be the correct diagram.
It has an element, air space, cemented pair, shutter/aperture blades, cemented pair. The element and pairs unscrew from the shutter and barrel.
Your haze may be cement failure in one of the pairs. Sometimes heat such as the pair submerged boiling water or heated in a oven to 300°F will clear the cement haze.
P.S.
I haven't dealt with Midwest Camera in about 20 years. They had a very good reputation at that time and likely still do.

 

[Dave Krueger]

Thanks, Dennis. That's good to know. Repair prices have gone way up at places like KEH, so I was pleasantly surprised that their quote was quite reasonable.

I've dealt with them recently, and they still do a fantastic job. I've had a couple of Ilex shutters repaired and timed, as well as some other more mundane work, and they are great folks to work with.

 

[shutterfinger]

There's a guy on youtube who cleans the inner elements with lighter fluid with acetone. Is that the way to go?

I will not use lighterfluid on anything and charge double to service anything that has had lighterfluid used on it. Acetone is useful to dissolve the thread locker used on retainer rings and screws in cameras and lens.
My breath and a heavyweight microfiber lens cleaning cloth usually work well on lens. 90% Isopropyl Alcohol and lens cleaning fluid are safe to use on lens.

Assuming it is, are repair shops able to separate and re-glue the lens elements or is heat treating them the only solution?

This I do not know. I had a Goerz Dagor that had heavy haze due to cement failure. I attempted to recement it myself but could not get the elements to separate. I only heated it to 300°F but according to SK Grimes it needs to be heated to 350°F (the recementing page on their site is gone). After repeated heating in a oven to 275°F and submersing in boiling water, letting it cool slowly it did not clear but after a few weeks it was clear. A Rolleiflex Automat rear cell retainer ring was stuck and the Acetone I poured around the ring seeped into the cemented pair causing splotchy haze. I put the rear cell in a 2 cup stainless steel bowl, covered with water then placed in a toaster oven on 300°F for 30 minutes. I let it cool slowly in the oven. When I removed it the haze was gone but the lines that were in the cell remained. Thunder storms ran through the area and started the wildfires currently on the news before I got out to run some film through it. This is my only experience with failed lens cement. UV cement is removed with solvent such as Acetone depending on brand. https://www.edmundoptics.com/f/norland-optical-adhesives/11818/

 

[Dave Krueger]

I will not use lighterfluid on anything and charge double to service anything that has had lighterfluid used on it. Acetone is useful to dissolve the thread locker used on retainer rings and screws in cameras and lens.
My breath and a heavyweight microfiber lens cleaning cloth usually work well on lens. 90% Isopropyl Alcohol and lens cleaning fluid are safe to use on lens.

I watched the video again and he was using acetone to dissolve the thread locker, as you suggested. He was cleaning the lenses with hydrogen peroxide and lighter fluid (not at the same time, of course). From the videos, it looks like the front and rear lens groups can be removed from Mamiya lenses without much disassembly of the lens body. Since the shutter works fine, I am now seriously considering doing the job myself and have looked up the tools in Amazon. If there are problems with glued element, I'll cross that bridge when I get there.

 

[shutterfinger]

He was cleaning the lenses with hydrogen peroxide and lighter fluid (not at the same time, of course).

Very strong chemicals for lens. Hydrogen Peroxide is used by many here for fungus on lens cleaning. Lighter fluid is Naphtha with some other ingredients. I do not recommend its use for any purpose other than starting a fire.

 

[PonySoldier1887]

I have gotten really good service from Mark Hama (near Atlanta). In my experience (over 45 years with Mamiya) the haze usually stems from evaporation of volatiles from lubricants and is easily removed but I still would not recommend that a novice attempt this. If it is a "beater" lens that you don't value by all means go ahead.
(Google "Mark Hama" for contact info- I have a Nikkor lens which I will be sending to Mark for a CLA within the next few days.)
Joel

 

[Dave Krueger]

Thanks for the info, Joel. I'll check it out.

I have gotten really good service from Mark Hama (near Atlanta). In my experience (over 45 years with Mamiya) the haze usually stems from evaporation of volatiles from lubricants and is easily removed but I still would not recommend that a novice attempt this. If it is a "beater" lens that you don't value by all means go ahead.
(Google "Mark Hama" for contact info- I have a Nikkor lens which I will be sending to Mark for a CLA within the next few days.)
Joel

 

[Dave Krueger]

Joel,

If you don't mind my asking, what aspects of this procedure do you think are most challenging for a novice? It looks like the lens groups on this lens can be removed and disassembled without having to do much disassembly of the lens body. My biggest worry at this point is that the retaining rings will require too much force to remove. If a tool slips, I could potentially damage the glass. I don't have any beater lenses for the RB, although I do have an old Nikkor 35-70mm that has problem with the aperture actuator.

... I still would not recommend that a novice attempt this. If it is a "beater" lens that you don't value by all means go ahead.
Joel

 

[PonySoldier1887]

Dave,
Having the correct spanner and a means to safely secure the lens while working on it. Frequently a "thread-locker" was used at the time of assembly; safely and completely dissolving this is essential to removing the locking ring without deforming the keyway slots. Too many folks either fail to remove (dissolve ) the thread-locker or flood the ring with too much solvent (usually acetone). Consider that lens coatings are metallic salts evaporated onto the lens surfaces and you can easily see why coatings are so easily damaged.
Joel

 

[shutterfinger]

I apply Acetone to the threads only with a cotton swab saturated with the Acetone.
+1 for too much will do damage.
https://www.ebay.com/itm/3-in-1-Spa...333542?hash=item2f457dc626:g:eC8AAOSwR25e8bMp

 

[Dave Krueger]

Thanks for the pointers, guys. I have tools on order and will see how it goes.

 

[Dave Krueger]

Joel,

How do you secure a lens to work on it. In the videos I've watched, they are just holding the lens.

Dave,
Having the correct spanner and a means to safely secure the lens while working on it.
Joel

 

[PonySoldier1887]

That is one way... there are other devices. The main thing is having a flat surface with a padding or light covering beneath the lens so that it (or any screws or parts) are visible and "captive" - can't fall.
Good luck! It isn't that big a job if you are attentive and methodical.
Joel

 

[chris77]

Have you considered doing it yourself?
This Mamiya service manual https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Lenses-Service.pdf should cover your lens. LE103 C on pdf page 58 should be the correct diagram.
It has an element, air space, cemented pair, shutter/aperture blades, cemented pair. The element and pairs unscrew from the shutter and barrel.
Your haze may be cement failure in one of the pairs. Sometimes heat such as the pair submerged boiling water or heated in a oven to 300°F will clear the cement haze.
P.S.
I haven't dealt with Midwest Camera in about 20 years. They had a very good reputation at that time and likely still do.

Great website.
Great repair manual.
Does something similar exist for rz67 lenses??

 

[shutterfinger]

https://learncamerarepair.com/productlist.php?category=2&secondary=22 ?

 

[chris77]

https://learncamerarepair.com/productlist.php?category=2&secondary=22 ?

Tx , but no rz67 kens manuals here.

 

[Dave Krueger]

Well, my tools are supposed to arrive today, but I went to Lowes and got a 2" to 1.5" rubber pipe coupler which worked great to loosen the nameplate ring on the front. I'm assuming there was no thread lock holding it on, but I was worried I it might be tough to loosen it based on a youtube video I saw. Maybe I'll do a blog post or video on this adventure, so other people can see how it went (unless I completely destroy the lens).

 

[M Carter]

Well, my tools are supposed to arrive today, but I went to Lowes and got a 2" to 1.5" rubber pipe coupler which worked great to loosen the nameplate ring on the front. I'm assuming there was no thread lock holding it on, but I was worried I it might be tough to loosen it based on a youtube video I saw. Maybe I'll do a blog post or video on this adventure, so other people can see how it went (unless I completely destroy the lens).

I've stripped one RB lens down to the shutter, and several more I've opened up to clean elements - I've never come across any sort of thread locker.

One thing I'll say though - even if your shutter is fine now, it will eventually seize. I have 7 RB lenses and currently three are frozen, one I repaired under the guidance of a forum member here. As long as you're in there, consider a solid shutter cleaning and properly lubing it per the service manual and you're good for 30 or 40 more years. The member here had me strip it down to the shutter without the shutter cover, and soak it in white gas (coleman fuel) outdoors (that shit is explosive and has no business indoors!) with a couple changes of fluid. The first soak released a fair amount of black crud. IIRC, some light oil (brass instrument valve oil) on the gear pintels and a microscopic smear of grease here and there. The manual likely clarifies the lube points.

 

[Dave Krueger]

Thanks for the advice. I do remember reading in a forum post somewhere that a fogged lens means shutter problems aren't far behind. I will look into it and see if it's within my mechanical aptitude. On the other hand, the shutter seems to work just fine as it is and, being that I'm pretty old, I may just gamble that I'll be dead before the shutter needs work.

I've stripped one RB lens down to the shutter, and several more I've opened up to clean elements - I've never come across any sort of thread locker.

One thing I'll say though - even if your shutter is fine now, it will eventually seize.

 

[Dave Krueger]

Bad news. The fog is between the glued elements in the front group. I was able to remove the front and back lens groups without resorting to any thread locker solvents and all the lens surfaces were pristine. The rear glued elements had no fog. I could see the fogged surface on the front lens pair by shining a light through it and it was clear that the surface that lit up was internal.

The next step is to try the heat approach described by shutterfinger. Otherwise I will investigate to see if I can send the glued pair off to someone who can separate, clean, and reglue them. My hope is starting to fade...

 

[Dave Krueger]

Well, I ordered a used "near mint" ("No fog, fungus, mold, etc.") 127mm K/L lens from ebay and it came today, but has haze on the rear lens group that lights up when I shine a light through the lens. See attached pics. Very disappointing. Maybe RB-67 lenses just don't age well.