Mamiya TLR lens cleaning advice

So after a fairly good track record buying lenses off of "that" auction site, I won an auction for a 135mm f/4.5 chrome-shutter lens. The seller said "light haze". I'm glad I didn't pay very much, because when I first examined the lens with a strong light, it didn't look bad. Then I changed angles, and now I know what "strong haze" looks like. Both rear elements have a nearly uniform coating of haze across the "inside" rear element (the flat surface facing the front element). The viewing lens has had mild fungus at some point, but enough to etch the coating.

 

So far, I've tried lens cleaning fluid, mild peroxide, alcohol (basic 70% isopropyl) and of course, glass cleaner. I didn't want to overdo it, I'd rather under-clean than damage the element.

 

So far the only result is a mocking silence as the cleaning fluids dry up, and the haze returns. :)

 

Any suggestions?

I believe Mamiya TLR lenses are made, not of glass, but of fungus candy. It's just a huge problem with all of them. I take mine apart about once a year for cleaning. It's typically the inside surface of the rear group that gets it the worst, but any surface might have it. Try the well known mixture of ammonia and peroxide, but don't hope for much. I don't know if the old lenses are even coated on the inside. On mine, the damage is right into the surface of the glass. With the right lighting I can see some horizontal lines in the surface that match the original appearance of the fungus. I bought some lens makers pitch and cerium oxide to try and repolish the surface, but haven't gotten around to trying it. Not for the faint of heart, but with a bad enough lens I'm willing to try it.

Their irritating tendency toward chalky haze buildup is one of the few buzzkills with Mamiya TLR lenses. It is unlike the fungus or haze typically seen with other lenses: its almost as if Mamiya's coatings and glass surfaces self-pulverize or grow a layer of powdery chalky yuck over themselves. Fortunately most focal lengths are easy to disassemble for cleaning access, and the haze usually comes off quickly and completely with a soft cloth and straight undiluted 3% peroxide, looking good as new afterward. Occasionally I've had an element haze so badly its basically etched in the surface like fungus, so theres no removing it. In such cases I either replace the optical cell or element with one harvested from a donor lens, or replace the lens entirely. Of my two complete sets of lenses from 55mm thru 180mm Super, I'd say approx half will frustratingly re-haze a year or so after each cleaning: it comes back repeatedly.

 

The traditional recommendation for cleaning haze and fungus is a combo solution of peroxide and ammonia, but I never seem to have ammonia around at the same time as a problem lens, and straight peroxide has almost always done the trick for me with lenses that aren't obvious trainwrecks.

 

With dirt cheap parts lenses, I'll sometimes try denatured alcohol (methylated spirits) or naptha, which sometimes removes stubborn haze that peroxide can't handle, but I wouldn't risk this on any lens that cost real money or I considered worth more serious salvage efforts.

 

You might double check that you're cleaning the correct surface: some of the Mamiya lenses are deceptive (the surface that looks hazed is is actually behind where it appears to be). Of the many, many lens pairs I've owned over the years, only a couple had actual organic fungus of the kind recognizable from other brand lenses (spider, droplets, rainbow, etc). Mostly the Mamiya TLR lenses develop this inexplicable thick chalky haze, often with evenly spaced streak lines that almost appear synthetic. An absolute mystery how or why this repeatedly manifests: with no focus helicoid, theres really no lube or other source material to outgas and form haze, other than glass and metal.

 

Anyway, good luck!

Edited May 29, 2020 by orsetto

I've noticed, and this may be a complete coincidence, that the two lenses that didn't come with a leather case, are nice and shiny. The 135mm which came in the original leather case... well. Its a small sample size. :)

 

How hard is it to remove the rear element from the housing? I can get the rear housing loose, that's no problem... but was considering stronger solutions, most of which would damage what appears to be a plastic mounting.

 

I'm fairly certain I'm looking at the right surface-- when I wet just that surface, the haze vanishes. When it dries, the haze returns.

I've never seen glass self-etch or pulverize, so I've been pretty sure it's fungus. If somebody could figure it out for sure, I'd love to know the answer. My guess is it's just the particular formula of optical glass they used, as some of them are known to be quite soft and fragile. I don't think any solvents that would damage plastics (acetone, toluol, MEK, naphtha, etc.) would have any effect on it, but the groups do unscrew like any others. I've found very tight lenses can be gotten apart with a rubber strap wrench; just be sure any locking set screws are removed first. I haven't tried the acid groups. Strong lab cleaners like Alconox didn't help, but I do use those in the ultrasonic cleaner for the housings to hopefully kill off anything living in there.

 

Having a lens with the above described parallel lines, I can tell you that minor repolishing efforts failed to remove them. That says they're extremely deep in optical terms.

 

For minor haze I've seen the recommendation of using cold cream, but I've never had any success with that.

How hard is it to remove the rear element from the housing? I can get the rear housing loose, that's no problem... but was considering stronger solutions, most of which would damage what appears to be a plastic mounting.

 

If by "rear housing" you mean the rear element inside its independent barrel cone unscrewed from the front element cell, removing the glass itself from the cone might be difficult. The rear element retaining ring on 135s I've owned is saturated in lacquer or LockTite: unscrewing it appeared to require a solvent stronger then methylated spirits, or brute force with a wrench, neither of which I wanted to try with the glass so exposed. Its easy enough to get at both sides of the single element within its cone, if its so etched and far gone that you can't get it clear inside the cone then removing it is unlikely to achieve better results.

 

Its been awhile since I had a silver face 135 open, the later black barrel (below) has a metal retaining ring (not plastic). I don't imagine Mamiya would have used plastic rings in the older lens and upgrade to metal in the new: yours is likely metal as well if the removed cone resembles mine. If the haze is on the taking lens but the viewing lens is clear (or at least nicer), consider just swapping the viewing and taking lenses. While this is frowned upon officially in Mamiya TLR enthusiast circles, secretly we've all done it at least once and its usually no problem optically. Mamiya really didn't make separate inferior viewing lenses: they're essentially identical to the taking lenses, and aside from a few very early examples with tiny custom shims the lenses are fairly uniform so you simply unscrew the four barrels and swap top to bottom. A heavily hazed taking lens often still functions surprisingly well as a viewing lens.

 

Or, just look for another complete clean 135 lens and use it as a glass donor, or total replacement for your existing lens. The 135 is the least popular, most available Mamiya TLR lens so it often sells for very low prices, esp with a bad shutter. Easy to find when you need another.

 

Edited May 30, 2020 by orsetto

I've posted this pic before in a similar thread: this is the haze I get repeatedly in my Mamiya 55mm, 105mm and 135mm TLR lenses. While some owners feel its more likely to be a fungus, my experience tends otherwise. I've never had a fungus that looked like this, and it does most often manifest as a moist-looking film more akin to haze. I've only had one or two lenses where this haze permanently etched the glass: normally it wipes cleanly off with peroxide leaving no trace behind. In half the afflicted lenses it never returns, in half it slowly reforms until a year or 18 months later its noticeable enough to prompt cleaning again. Almost always it forms in this evenly striped pattern, something I've never seen fungus do (and I've actually never had fungus return after a thorough peroxide cleaning, not even in a Hasselblad 150mm Sonnar I got for $25 at a garage sale because it was thoroughly occluded with fungus on every element from being stored years in that garage). YMMV.

 

If by "rear housing" you mean the rear element inside its independent barrel cone unscrewed from the front element cell, removing the glass itself from the cone might be difficult. The rear element retaining ring on 135s I've owned is saturated in lacquer or LockTite: unscrewing it appeared to require a solvent stronger then methylated spirits, or brute force with a wrench, neither of which I wanted to try with the glass so exposed. Its easy enough to get at both sides of the single element within its cone, if its so etched and far gone that you can't get it clear inside the cone then removing it is unlikely to achieve better results.

 

So noted.

 

The middle unit in the second picture is where the problem is, inside the cup:

 

 

The white specks are probably dust or lint-- both rear elements are like this, and I think I took a photo of the one I haven't tried to clean. I'm sure it's fungus, just don't know how permanent it is. I'll seek out stronger (and fresher) peroxide tomorrow.

That's definitely different from what I have, which is pretty benign and easily removed. Your pic does look like fungus might be involved (the dark spots): possibly the haze and fungus coincided, and the fungal excretions that can etch the glass ate thru the haze to do so, in effect etching the haze into the glass as well. If you can't get it completely off with fresh peroxide or a peroxide/ammonia solution, its unlikely to come off any other way short of an optical shop re-polishing the glass. That isn't cost effective with the Mamiya 135mm TLR pair, since you can typically pick up another clean 135 for as little as $69 (USD) within two weeks of eBay hunting.

 

The damage in your pic also resembles element separation caused by decay or fungal interference in the adhesive layer. All this time I vaguely assumed the rear element in the cup was a single element, because mine always cleans so easily and seems thin. But when I checked the 135 optical diagram in my Mamiya archives just now, I noticed the rear element may actually be a cemented doublet (with two single-element groups in the front cone). If my diagram is correct, your issue is probably in the cement sandwiched between the rear element halves, which is a very difficult cleaning repair.

 

You'd need to get the retaining ring off somehow without ruining its threads or shape, separate the glass doublet by soaking in solvent until the old adhesive melts off, then re-cement the two halves with fresh optical adhesive. People have posted here about performing this repair, its doable, but only makes sense if you already have the adhesive on hand and some experience with similar previous repairs. Hardly seems worth the trouble for such an inexpensive lens, but if you enjoy a challenge it might be a fun project.

Edited May 30, 2020 by orsetto

I had pretty much concluded the same, except I'm reasonably certain all that is on the surface. Then again, I have the lens in hand, and can do a better visual inspection than I can capture with a camera. I had considered the idea of trying to polish it, since it *does* appear to be a flat element, but that's for a rainy day when I've got nothing better to do than destroy a lens element :)

 

Still, I don't feel too bad-- I got a case, a fully working shutter, and 2 pretty fair front elements. Actually, the lens works far better than expected, as long as you don't have any sun coming into the lens. If I can find a 135mm with a busted shutter, I'm good.

 

Thanks to all of you for the time and advice given.

Pretty sure it's not flat, but has a slight curvature. I wish I knew the radius of everything as that would give me more confidence with a repolish. OTOH, if somebody can get a good reflection of a grid off an untouched one, that would help a lot.

My lens diagram archive is from an old long-dead Mamiya TLR fan site: it can be hard to verify some illustrations as authentic. Since now it really did seem a good idea to get confirmed info on the rear element block, I gave google a shake and tracked down the official Mamiya diagram for the 135mm black barrel (the older chrome has the same layout).

 

It is definitely a four element three group Tessar derivative, with two single airspaced front elements and a cemented doublet in the rear cone. So if surface cleaning continues to have zero lasting impact, ufgrat, you might well have a separation/decay/fungus issue in the rear group cement. A test for this would be gently running a fingernail across the surface: if the haze is not dislodged whatsoever, and you can't feel any roughness or drag, its likely between the elements instead of the outer surfaces. BTW I've always found the "external" positioning of the shutter and aperture blades (behind the rear element) in this lens intriguing: never seen another design like that.

 

Edited May 30, 2020 by orsetto

I knew nothing about these problems when I bought my C3. The camera looked reasonable on ebay and the price was very fair so I bought it. It was though, covered with dust, which made accessing the cosmetic condition more difficult, but when in my hands the lens glass (80mm) was defect free I noticed. I reasoned the dust was from breezy storage conditions which kept moisture to a minimum and oxygen to a maximum, two conditions fungus don't agree with, so I learned online, and it must be correct. I now try to duplicate those breezy conditions, minus the dust, by opening the display cabinet doors and turning on the ceiling fans every now and then. After some years on display, all my camera lenses are fungus free, only having normal room dust and lint specks.

Can somebody be able to clean my 80 mm lens for 645, 1000S? Please name the price and I will mail it you. I am not good at taking things apart and putting them together. I dont have the tools either! So far, only Pro camera is willing to touch mamiya lenses.

If the lens has fungus, does that mean the camera may have it too? Thank you very much!

...if these lenses are more prone to fungus than others it may not be solely down to the 'glass'. Could an 'oiled' focusing helix offer a 'protective' effect? Good to read how they may be dismantled.

My basic set of Mamiya lenses (65, 80, 135, 180) don't get left on the camera body if I am not using them for any length of time. Humidity is a villain I think, since fungus loves it. But I can't keep the house too dry or my guitars will crack and warp. Solution seems to keep the Mamiya lenses in a zip lock bags with a couple of desiccant packs. I grew up in coastal Florida and my dad was fungus phobic. He had cabinets with light bulbs inside that he kept all of his photo gear in.. Seemed to work pretty well, but these days zip lock and desiccant seems to be a simpler solution. Growing up is South Florida and working in tropical areas of Mexico teaches you a lot about preventing fungus. Like rust on tools, fungus never sleeps.