| Author |
Message |
    
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 27
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 04:48 am: | 
|
Hi,
I just got a Canon Canonet QL17 G-III that has seen better days. Everything seems to be working mechanically but among other things, there were 2 dents in the filter ring, making it hard to disassemble. Using a wooden dowel I was able to get it back to shape enough to take it apart. The front element has a problem. I thought it was fungus, but after careful cleaning it feels very smooth to the touch on both sides, yet I can't get it clear. Here is a picture of it.
http://images36.fotki.com/v1204/photos/4/1233394/8254878/IMGP1874b-vi.jpg
I don't think it is fungus. The element is quite thin so I don't think it is a cemented pair. Is this a common problem for these lenses? What is it? But most importantly, can it be saved?
Thanks,
Ismael |
Dirbel
Tinkerer
Username: Dirbel
Post Number: 26
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 05:12 am: |
|
What solvents did you try so far?
I once had to use lighter fluid to clean a lens ;isopropanol did not help in that case.
Dirk |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 28
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 05:50 am: |
|
I have tried isopropyl alcohol, lens cleaning solution, Fantastik household cleaner, lighter fluid and last night I tried a drop of chlorine bleach (thinking it could be some sort of hard fungus) but abolutely nothing happens.
I'm thinking of trying automotive polish since it is a bit abrassive, but there is no way I can keep it uniform. I may distort it permanently.
Thanks,
Ismael |
Dirbel
Tinkerer
Username: Dirbel
Post Number: 27
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 06:39 am: |
|
Just in case it is fungus: you might try vinegar - always worked for me so far.
Dirk |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 29
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 07:12 am: |
|
Thanks Dirk.
Just tried distilled white vinegar. Nothing. I think I can hear the lens laughing.
I even tried swirl removing auto polish and nothing.
Is this glass or could this be plastic? Are these lenses coated? Could this be coating failure? If it were fungus etching, Would I be able to feel it by touch?
Whatever it is is on the outside of the element. The other elements look fine and so does the inside of this one.
Anyone has a nuclear fission reactor cleaner?
Thanks,
Ismael |
Finnegan
Tinkerer
Username: Finnegan
Post Number: 19
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 18, 2009 - 11:16 am: |
|
It is glass. They are all coated (anything generally made after 1956 was coated).
Hmm, ok, looked at the pic. Well, you have nothing to lose so try everything. Try nail polish remover. Try  denture cleaner.
You know, it may be that soaking overnight in some of the stuff you tried already might soften it up. Maybe it is not the stuff you are using but the amount of time it needs to work. |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 30
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 19, 2009 - 04:39 am: |
|
I'm about to concede, accept defeat and declare it the winner.
12 hours dunked in lighter fluid. Nothing.
Overnight in Fantastik cleaner. Nothing.
Several hours in vinegar..... Nothing
I swear I can hear it laughing at me.....
If it comes to worst I'll just clearcoat it. It will pretty much destroy its functionality but it is unusable anyways. At least it will display a bit better.
Thanks,
Ismael |
Harryrag
Tinkerer
Username: Harryrag
Post Number: 148
Registered: 05-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 19, 2009 - 05:05 am: |
|
Here's my two cents on the matter, Ismael, I once received a badly tortured vintage spares Minolta that had a front lens that looked similar to your Canon's. Like you I tried everything with no success at all. Finally I inspected the lens with a strong magnifying loupe and found deep lunar impact craters somehow worked into the glass, in parts it looked like someone had sandblasted the lens!
I never found out how this state of the front glass came about, as the camera had changed hands several times, but I gave up trying to restore/reshape it. Take my advice: forget about this one, get yourself a junker with a functional front lens for replacement, in the case of which you have to readjust proper infinity focus, and dispose of the defective one in the garbage can. |
Dirbel
Tinkerer
Username: Dirbel
Post Number: 28
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 19, 2009 - 05:08 am: |
|
Searching for 'lens polish' in this forum gives several hits, for instance:
https://kyp.hauslendale.com/classics/forum/messages/13061/9234.html
https://kyp.hauslendale.com/classics/forum/messages/2/14889.html
https://kyp.hauslendale.com/classics/forum/messages/13061/8611.html
Polishing the lens will not neccesarily make it useless (if you're careful).
Dirk |
Harryrag
Tinkerer
Username: Harryrag
Post Number: 149
Registered: 05-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 19, 2009 - 07:05 am: |
|
In this case I bet it definitely WILL, you can trust my experience here, that was why I wrote "All this polishing business is a kind of worst case measure, it usually signifies the beginning of the final stage in the lifetime of a lens." And, yes, it does affect picture quality, of course. |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 31
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 19, 2009 - 09:34 am: |
|
Any chance this could be a cemented pair and I'm looking at cement failure? Been quite thin I thought it was a single chunk of glass, but looking at it thru a magnifier, the surfaces on both sides are very smooth.
I'll just put it back together for display. Maybe later I can get a replacement front element.
Thanks,
Ismael |
Ezio
Tinkerer
Username: Ezio
Post Number: 19
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 22, 2009 - 01:04 pm: |
|
I also had a GIII with a lens looking exactly as yours, and I went through your very road without success. Eventually I had to concede that what looked like sort of fungus was actually massive scratching and thus beyond repair. Apparently our cameras were both previously owned by someone who used sand paper to clean the lenses.
I would suggest that you do what I did: buy a badly mauled/non-working GIII with a clean lens, and simply swap the damaged element. |
Tgraichen
Tinkerer
Username: Tgraichen
Post Number: 3
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 15, 2010 - 03:57 pm: |
|
i have a GIII with a very similar looking front element and after failing the cleaning road like you i realized, that the element is fine while looking though it, but looks horrible if lights is coming or if i'm looking from the side. at the end i simly reassembled the camera (after nearly having given up on it), put some film in and tried it with a lens hood and the results were surprisingly good: the lens is still one of the shapest i have seen and it flares only slightly more in direct light then it would maybe do otherwise (i think the canonets flare a lot also with a fine lens). and all that even with a similar, but smaller damage on the inner element of the lens as well. what i have learned once more is that a lens must have quite some problems until you will really notice it in its optical results. |
Canonet_giii
Tinkerer
Username: Canonet_giii
Post Number: 1
Registered: 06-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 05, 2010 - 08:29 am: |
|
Hey all, One item to mention this lens is fused to the coating from the factory. The lens is pointed in the center so upon the process to fuse the coating on it will be 100 percent centered. The lens you show in your website page is riddled with fungus under the coating. It is worthless to fix for it can't be done. If you like let this lens soak in peroxide overnight. In the morning you will have no coating and can see the center point is this lens. After rebuilding these Canonet's for 30 plus years I can tell you about anything you want to know |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 93
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 08, 2010 - 12:54 pm: |
|
Alright, this isn't a question about a GIII, but with the experts here I thought I would ask.
I have a Canonet 28 with a film winder problem. The take up spool tends to spin rather than pulling the film through. This leaves just the sprockets to advance the film and leads to tearing.
If I push down on the plastic take-up spool, it seems to have more resistance when rotating and will pull the film properly.
Has anyone encountered this? It I was to dissassemble, would it be easier/better to go from the top or bottom? |
Silverimagelimited
Tinkerer
Username: Silverimagelimited
Post Number: 1
Registered: 01-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 20, 2011 - 08:51 am: |
|
Hello all.
I myself have a GIII 1.7 with a fungi on the inside of the front elements. I am pretty good with most things but I have a question: You're all bantering about opening up and slapping together as if this seikosha nuisance were easy to open and shut. Is there a way to remove the plastic cover ring without mangling it beyond help? And will a standard lens spanner get the job done once I get under there? Thanks. |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 36
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 20, 2011 - 07:59 pm: |
|
Ismael,
After looking at the teardown drawing for your camera, it certainly looks like a cemented pair. Two elements in front of the shutter, and two elements in the rear. I seem to recall reading this is a four element lens. I don't think you will be able to repair this, except by replacement of the elements. After the shock it took to the filter ring (two dents) it is probably seperation of the elements.
PF |
