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Natew
Tinkerer
Username: Natew
Post Number: 1
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 19, 2009 - 07:01 pm: | 
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Hi! I've got a Mamiya C3 that my dad got before I was born. It's not been used since ball park 40 years ago, either.
I expressed an interest and my dad let me at it.
What I've discovered, though, is that the lenses I've got with it (80mm and 180mm) both are in need of some pretty significant cleaning.
The 180 is especially bad off and I'd like to clean it.
I've had the front elements off and used the bulb/f4.5 approach to make sure I couldn't clean it without further disassembly. No joy. The grit inside the lens (and fogging) appear to be inside the rear lens pack, leading me to think I'll have to take the rearmost element off to clean it properly.
So, before doing this, I'm asking around a little. 
The 80mm also had 2 or three good sized fungus problems, but I cleaned them off already without apparent long term problems. We'll see when it gets to long term.
Thanks for the help with my semi-non-functional 180mm!
Nate |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 985
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 20, 2009 - 07:44 am: |
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It looks like your problem, as you say, is internal to the rear cell. This may not be real good news, as there is no way for dirt or oil vapor to have gotten in there, so it may be deterioration of the coating or cement. I don't have any C lenses here... it looks like there is a slotted spanner ring at the rear end of your lenses, so it should be possible to unscrew that ring and get a look at the inner surfaces of the elements. On the fungus issue, keep a close eye on that lens and reclean at the first sign of a recurrence: fungus cleans off easily enough, generally, but if left too long will do permanent damage to the glass. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 167
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 20, 2009 - 05:56 pm: |
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You will have to open the lens, take off the front n rear cells n see if the dirt can be cleaned. Don't mix up the viewing n taking lenses n don't lose the shims.
I hate to say this but what I see in your pics may be fungus. Hard to tell for sure without seeing it on the bench.
You can buy good used lenses for a reasonable price. Cleaning the body yourself is easy enough with a few basic tools. If you are daring, cleaning the lens is not such a big deal either but will require some patience, and research, brefore you actually do anything, perhaps a bit of a learning curve for a newbie. Get a few old junker folders wit leaf shutters to play with first so there is nothing to lose.
I guarantee you will have fun, gain a new hobby, and perhaps get bitten by the bug... DIY camera restorations. We are all junkies in a sence and no matter how hard we try to clean out the closet of our treasures, it's difficult to let go of a single one. Adopting new members is habbit forming though. |
Jaywarner
Tinkerer
Username: Jaywarner
Post Number: 1
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 20, 2009 - 08:44 pm: |
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I'm the guy who "lent" Natew the Mamiya, and I resent that "40 year" bit. More like 30, or 25 years. What was the expiration on the old film it had?
As for pulling apart the lens to clean it, I agree with Paul_ron: Keep the pieces associated with the lenses they started with, and remember that positioning of the lens parts will influence the focal length of the lens. And each lens MUST focus at the same focal length. |
Natew
Tinkerer
Username: Natew
Post Number: 2
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 20, 2009 - 09:01 pm: |
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Yep, that's him right there, my dad. And I think there's a point to the less than 40 years. (I forgot the expired film in the case! 1991...)
Thanks to everyone for the help! Lots of good info, and quickly, too. Perfect for an impatient perfectionist like me. (OK, that description's not very accurate, either.)
So, I'm an engineer who's been disassembling things since I was a year old. (Er hm. Putting back together came later, I think. Er hm.) What's a guy supposed to do when it's past bed time and the latest book off the shelf is already finished? Why, fabricate a spanner wrench of the right size and take the lens apart, what else?!?
So: the spots appear to have been fungus and are all gone.
The inner surface of the inner lens of the rear pack was at fault here. The fogging did _not_ go away so I suspect there's something with a coating breaking down or related. Being a newbie, I'm not trying for a formal diagnosis here, but based on the above comments, it looks like this could be it.
Next: the viewing lens is much clearer than the taking lens. Since the lenses appear to be identical to the naked eye, is the suggestion against swapping for something other than rule of thumb? It's a risk balance: clear glass = better picture, but swapped glass = worse picture. Which is the stronger possibility?
Also a possibility: swapping all the glass from taking to viewing side; this would keep the matched set while getting clearer glass for the taking lens. Of course, if there's some difference between how the taking and viewing lenses are set up besides as matched pairs...
Any thoughts?
Thank you!
Jay's kid (Nate) |
Mikel
Tinkerer
Username: Mikel
Post Number: 166
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 20, 2009 - 09:31 pm: |
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It's difficult for anything more than a wild guess.
The viewing and taking lenses may be identical and interchangeable; it was done in the 50's and 60's on several brands of TLR's. I have no idea about the Mamiya.
The only important difference in the viewing and taking lenses that would come to mind would be that the taking lens incorporates an iris diaphragm and it is the lubrication from this which has probably deteriorated over time and fogged the adjacent lens surface.
You might try some of the more robust methods of cleaning the fogged lens. If all else fails, come back and I will give you a last resort method which used to be in the archives before 2004. |
Natew
Tinkerer
Username: Natew
Post Number: 3
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 21, 2009 - 04:33 am: |
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Mikel-
I did a somewhat poor job of describing where the problem was: from the rear of the lens, talking by surface number (i.e.: 1 is the most readily available surface), the problem is on surface 3 (not directly adjacent to anything but the glass of surface 2).
There may be some additional problem on surface 4, which _is_ next to the aperture, but neither breathed fog, nor spit, nor alcohol based Zeiss lens cloths have been able to remove it even after extended (3-4 minutes) scrubbing with the paper of the wipe or (he says sheepishly) my shirt. (I figured the shirt fibers were more rough, but not so much to actually scratch the glass...)
Any suggestions on a more "robust" method? Seems like something one wouldn't want to experiment with without some prior knowledge. (I'll search the forum, too.)
Thanks!
NateW
BTW: the viewing and taking lenses appear to be different only by serial numbers; all other writing on them is identical. The serial numbers are pretty different, though: No.774972 (viewing) and no.97484 (taking). It looks like they did a good job of reusing designed parts, too: even the extension tubes (from the lens board to the front lens packs) appears to be identical. When I had the glass of from the rearmost elements of the two lenses off, I couldn't visually see a difference.
If nothing else works, I may try setting up a shot in my studio (read: repeatable image) and shooting one as is and one swapped and checking the results. It'd be a longer process than I'd love to have, but it should be functional just the same. Thanks! |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 986
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 21, 2009 - 04:33 pm: |
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The durability of lens coatings varies dramatically. With some, the first touch ruins it - some are harder than the glass under them. I have a Kowa lens that had a badly fogged coating, the cause of which I don't know - while I would not have done this if I could see any other way to salvage the lens, I went to polish off the coating with Simichrome metal polish, expecting to lose the coating but also the haze. As it happened, the coating was so hard that I could not polish it off, and it took a lot of elbow grease to make a big dent in the haze. I did manage to get it to a usable condition, though some haze is still visible in it. I don't necessarily recommend taking this approach, it's a crap shoot. The coating is about 0.1 microns thick, so if you haven't removed the coating you're not likely to have altered the contour of the lens surface in any meaningful way... if you do remove the coating, stop immediately at that point, because it's the only signpost you've got to know you haven't messed up the lens. The loss of a surface of coating will reduce contrast, but it will be better than what you're looking at right now. |
Mikel
Tinkerer
Username: Mikel
Post Number: 167
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 21, 2009 - 05:52 pm: |
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Nate-
In reviewing some of my earlier notes, it appears very possible that the Mamiya C Series TLR lenses are interchangeable between viewing and taking lenses.
As for the last resort method of cleaning lenses, it was a desperation method learned in attempting to clean the front surface of the rear cemented doublet (Tessar formula) of a Petri 45mm 2.8 on a Color Super of 1958 or so, which had resisted all attempts.
The problem was finally solved with tartar control toothpaste, with some water for lubrication. I hesitate, as I did here years ago, to pass this on, but it worked for me and the feedback of other's results were positive. I don't think that any lenses were ruined which were not already in that condition.
As Rick says, YMMV regarding the durability of lens coatings, and you are now on your own. But it seems that the old deep purple coatings were sometimes harder than the glass they coated, and they were exceptionally durable. |
Natew
Tinkerer
Username: Natew
Post Number: 4
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 21, 2009 - 08:29 pm: |
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Thanks Rick and Mikel! I'll put your comments to good use.
Here's the plan at this point: as long as my dad agrees, I'm thinking to try a little polishing.
My wife was a glass engineer in a previous life (automotive glass) and had some experience in the lab there. She suggested using those white bar things. (You know, the Mr. Clean wipe away things? Others have them as well (Target, etc.).)
Based on her experience/knowledge: toothpaste and those bars are basically very similar, just that toothpaste is a coarser grit. Her previous employer used the bars for polishing glass, but she did mention that if you really get on something, it's going to wear the glass itself, even a noticeable amount (which on a lens might not be much).
One other thing she was thinking: the fogging might be etched glass instead of a coating gone bad. Either way could be tough. I'm thinking to try out polishing the taking lens first (because it's worse off, and I can swap them if I need to later), though I'll need to fabricate a new spanner wrench for it first (the one I already made doesn't have the depth needed).
I'll let you know how it comes out. (Could be a couple days, we'll see how much time I have.)
Thanks!
Nate |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 168
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 22, 2009 - 06:39 pm: |
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I've swapped viewing lens for taking lens. The coatings are different, the focal lengths are the same. You'll have to adjsut the film plane to view screen again in order to get crisp pics. You'll pick up some flare but with carefull attension to your surroundings you'll get nice results. After all, you have nothing to lose at this point, so why not have fun with it instead of trashing it. |
Mikel
Tinkerer
Username: Mikel
Post Number: 169
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 22, 2009 - 10:39 pm: |
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That's right- it's a last resort kind of thing.
I hope everyone who reads this understands it.
If the glass is already etched, there is little left to lose. It's up to you. It worked for me.
BTW I'm going to meet the chemical engineer who holds the patent on tartar control toothpaste. Seems his daughter and my son are getting along well. I'll be asking about this at some point. |
Jaywarner
Tinkerer
Username: Jaywarner
Post Number: 2
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 23, 2009 - 07:24 pm: |
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OK, we've gone past the point of planning to do a full restore on the lens. Does anyone know a professional camera repair person who might know how? And hasn't retired? Natew - any idea what a replacement lens might go for on-line? In case nothing works out?
the tarter removing toothpaste seems unlikely, inasmuch as it _does_ have some soft abrasive in it. But it has worked before...
I was under the impression that these lenses were in two groups, one on each side of the shutter. If lens elements are cemented together, there is less internal reflection, less flare, and better contrast in the image, than compared to separated elements. Plus, if you disturb the cement between elements... never mind.
I doubt you could visually see a difference in the taking and viewing lens in terms of focal length. That has to be the same, so that they will both focus together (the same mounting thread-to-film plane distance) for all subject distances. If you calculate out the depth of field at f/4.5 and 2 m subject distance, you will see what sort of precision was necessary. As Paul_ron says, the coatings could well be different.
But whatever you do, I'm glad I'm not watching. It is a wonderful camera, film and all. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 169
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 24, 2009 - 01:39 pm: |
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There are plenty of hobbiests that do this sort of thing all the time. Professioanls, there are a few n charge way too much concidering a used lens in good shape is only $120. Pay someone $100 to do a CLA on a fungus lens, not worth it sicne they won't change the bad glass, only clean it as best as possable, or sell you another lens. Most retired camera guys still doing it out of their basements, like me, still charge too much for what the lens is worth.
DIY and have a blast. Buy another lens and still DIY and have a learning experiance. Sell the bad lens for parts, don't expect to get much for it, n buy a better one.
Check KEH,
http://www.keh.com/OnLineStore/ProductList.aspx?Mode=searchproducts&item=0&Activ ateTOC2=false&ID=&Size=&BC=MT&BCC=5&CC=&CCC=2&BCL=&GBC=&GCC=&KW=
for a bargain graded lens, also check PhotoNet classified, I see em advertised all the time faily cheap but don't buy it off Flea-Bay, you'll wind up with another junker fungus lens. |
Natew
Tinkerer
Username: Natew
Post Number: 5
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 11, 2009 - 06:08 pm: |
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OK, so after being so busy, I finally got to working on this. Here's the post-work picture to date.
Operations performed so far:
* Removal of rearmost element and clean outer element & rear side of inner element with a couple of non-threatening fluids (cleaned off "living" (?) fungus)
* (eventually) removal and polish of inner rear element (taking lens only) with white cleaning sponge stuff & non-tartar control gel-type toothpaste (couldn't find any of the tartar control type in the house).
* wash & reassemble.
The Polishing showed an almost immediate improvement, but despite 20 minutes or so of either cleaning sponge stuff or toothpaste (about even usage), I couldn't get any more of the fogging to go away.
It appears to be mostly on the rear surface of the inner element.
Looking on "Flea-Bay" (thanks Paul!), I noticed that most of the similar lenses around are in the same condition.
Now if I could just figure out how to do this to completely clean up the lens, I'd have a nice little repair thing going! Except, if it was easy, a lot of others would already be doing it.
We'll see how it shoots; I've not shot it 'cuz it was _so_ bad it didn't seem worth it.
Also struggling a bit with processing/scanning 120 size film... Seems like the number of places doing it is so small the price competitiveness of the remaining shops is not so good. Oh well, that's what you get for playing with old cameras and old film, I guess.
Thanks for your help and I'll re-post when I get some results.
Nate |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 171
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 11, 2009 - 07:22 pm: |
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Now if the kid married the tarter control's daughter, you can buy yourself a new camera.
Did you swap the viwer for the taker?
Did you check out KEH? |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 172
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 11, 2009 - 07:24 pm: |
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OH I forget, did you check hte focusing film plane to viewer? |
Natew
Tinkerer
Username: Natew
Post Number: 6
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 24, 2009 - 01:36 pm: |
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Well, I took a couple of shots, but I've not had them developed yet. We'll see how the results came out when I can afford to send them out for it. (I had 80mm and 180mm and got nice (?) shots of the multi-color fall swamp.)
I didn't end up swapping any lenses around; I was too worried about the effects of coating changes and wanted to see just how well the results I managed to get so far turned out.
I checked out KEH; prices were as expected (i.e.: enough to make me say: I'll so what I can with this one and try for the best).
I did not check film/viewer focus planes; honestly, I'm not sure how I might go about doing that other than taking pictures and seeing what happened later.
Any thoughts?
Nate |
Natew
Tinkerer
Username: Natew
Post Number: 7
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 25, 2009 - 03:25 pm: |
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Sorry, missed something: this is the location I shot the "test" shots at. Looking forward to the resulting images! (this shot with a Nikon D80 set to about as saturated as I can get; I hope it's about what I get from Velvia 50.)
 |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 173
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 27, 2009 - 03:41 pm: |
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You focus using a well lit target, then with a GG on the film plane focus using a loupe for max sharpness. If the view screen doesn't agree, the viewer is focused to match the film plane.
*I don't remeber if the lens itself can be focused by screwing it in n out of the mount or if the view screen gets adjusted.... it would be one or the other. |
Epatsellis
Tinkerer
Username: Epatsellis
Post Number: 12
Registered: 01-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 26, 2009 - 09:51 am: |
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Out of curiosity, have you tried cold cream rubbed by hand. Odd as it seems, it's saved my butt on some lenses that had the same type of fogging. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 179
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 27, 2009 - 05:29 pm: |
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I've heard about the cold cream but never tried it myself. I'll bet the lenses are baby butt soft n smooth? |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 24
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 27, 2009 - 07:27 pm: |
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I used cold cream a couple times on old (uncoated) lenses. It seemed to clean them, but then I read that you really shouldn't use this stuff on lenses, so I stopped doing it. It sounds like a fairly dodgy bit of DIY camera-repair mythology. |
Epatsellis
Tinkerer
Username: Epatsellis
Post Number: 13
Registered: 01-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 28, 2009 - 08:16 am: |
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perhaps, of course the "proper" way to repair the lens is to replace the elements. I've used other "dodgy" sounding approaches as well:
Rick Oleson's wicking light oil into the edge of a separated lens cell, full immersion soaks of (metal bladed) shutters to evaluate if I want to go any further, or if the shutter's worth the effort.
I've even cleaned heavily fogged elements from an Artar in the kitchen sink. Little bit of dishsoap and gently rub the elements clean, one by one.
How about de oiling an aperture on a lens via Qtip, before I disassemble totally to ensure that the few light scratches on the front element won't affect the image as badly as they look.
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David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 27
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 28, 2009 - 12:51 pm: |
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None of those other things that you described sound "iffy" to me, and I take any advice from Rick Oleson very seriously. But the cold cream thing is, to me, fairly worthless urban legend. |
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