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Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 16
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 10:07 am: | 
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Hello.
On a recently acquired FD 50mm f/1.4 lens, I have noticed that the diaphragm gets some kind of a fluid on it as it is worked. If I leave the lens aside for a while, that wetness disappears as if it has evaporated.
Also, on of the front elements has a slight haze on it (partial, around 40% of area) which is actually difficult to make out unless one looks for it specifically.
What can one make of the fluid like substance that disappears or evaporates from the blades?
Is oil supposed to behave like this?
Finally, is that drying of the fluid related to the haze in the lens?
Depending on the feedback I get, I might try to open the lens and try cleaning it.
Thanks for all inputs.
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David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 18
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 12:48 pm: |
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Dunno what the fluid is, but it doesn't matter: you don't want it there. Diaphragm blades should be bone-dry. That haze is probably whatever the fluid is, deposited on the inside of the lens. Should be easily removable with the usual lens cleaners. (I use Windex, and acetone when I really want to remove schmutz.)
If you can get the diaphragm out, it would be good to soak it in solvent (naphtha) to remove the fluid. |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 17
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 01:03 pm: |
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I suspect, though I may be wrong, that the fluid is coming from the inside mechanism of the lens and is not just on the blades.
In any case, does the behavior sound like it is oil? The fact that it is disappearing makes me think it is not oil, but am new to this. |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 20
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 01:22 pm: |
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Well, we can pretty much rule out it being water, which leaves any number of oil-based substances. It may not be oil per se, but is probably some kind of petroleum product. Could be some component of the grease used on the focusing helical, I suppose. But definitely some kind of oil-based fluid.
The important point is that it shouldn't be there at all. If you can't take the diaphragm out, but if you can gain access to the blades, you might want to carefully swab them with a Q-tip moistened with naphtha, which should remove most of the offending liquid. |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 18
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 01:45 pm: |
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I have noticed that the focusing ring is a bit hard to move. It does rotate, and is smooth, but takes some effort. Could this be related somehow? And the aperture ring is a bit too easy to move (the dedents are soft).
It is a Canon FD 50mm f/1.4 SSC lens. I have seen a hand drawing by someone on the web someplace showing how to take the front out and how to take the blades out as a unit to dowse it in naptha.
Finally, I wonder what experienced people say here regarding returning the lens for a refund as opposed to trying to fix it myself. To give better context, the lens is $50 approx in cost, shipping was $20 or so. I think I can return it, but I will be short of shipping cost.
Thanks. |
Gez
Tinkerer
Username: Gez
Post Number: 166
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 01:49 pm: |
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It's oil. The FD 50mm/1.4 made about 1977 are notorious for this problem. The oil doesn't evaporate, it merely spreads out onto the blades with increase in ambient temperature. There is lots in the archive on how to clean the 50/1.4 iris assembly, it comes out as a unit for easy cleaning. Removing the front optical cell may prove difficult, the use of a flexiclamp, either home-made or bought, is recommended. Before removing the iris unit measure the diameter of the aperture at F16. |
Tom_cheshire
Tinkerer
Username: Tom_cheshire
Post Number: 228
Registered: 04-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 24, 2009 - 02:34 pm: |
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It sounds very much like your newly acquired lens was "repaired" recently by a (choose the insulting word yourself) repairman.
The aperture probably has lighter fluid on it or some sort of degreaser spray. Those are the substances which will behave as you described.
The "soft" detents are the result of the spring or ball bearing having been lost during disassembly and replaced with the next best thing he had available.
If you want to clear the fluid and haze, place the lens in a very warm place for about a week. I had a Nikon 28mm with the front totally hazed. Thought it was a parts lens for sure. Left it on the shelf and ignored it for about 6 months. When I did pick it up to look it over again the glass had cleared beautifully and no trace of any problem.
Now, as for the price, I will only say with the utmost delicacy that I am amazed and somewhat hurt that I can not attract such generous buyers to purchase my pristine items on eBay (mainly having in mind the $30. smashed Yashica Lynx and $35. messed up Fujica V2 that were mentioned on this board by other posters). My stuff generates something like half these prices. |
Extrabroker
Tinkerer
Username: Extrabroker
Post Number: 7
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 26, 2009 - 02:39 am: |
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The front lens cell is a sealed piece. The haze is usually within the sealed piece. Unless there is a method to "unseal" that piece, then there is no way to remove the haze. |
