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Flashinm
Tinkerer
Username: Flashinm
Post Number: 10
Registered: 10-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 22, 2013 - 01:31 pm: | 
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I got this Nikon 35mm f1.4 AIS lens and it looks to be in excellent condition. However when looking at the front of the lens there are two silver rings with some crud around them. It looks almost like deteriorated foam. I have no idea what it is. Looking around at other pictures I see that some of them show the two silver rings, but most do not. Anyone know?
http://img.auctiva.com/imgdata/1/5/2/6/6/4/4/webimg/640934828_o.jpg |
Plaskey
Tinkerer
Username: Plaskey
Post Number: 18
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 23, 2013 - 03:18 am: |
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Looks to me as though the balsam (the cement used to fix lens elements to each other) is starting to oxidise at the very edges of the glass. It looks ugly but it's hard to say whether it would degrade optical quality. Needs a test film, or if you are using it on x1.5 crop digital it wouldn't make any difference. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1276
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 23, 2013 - 05:15 pm: |
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It could just be the black paint separating from the edge of the elements. Strong negative elements, often found on the front end of wide angle lenses, are thick at the edges and so have some glass edge surface that is not captured in the retaining rings. These edges are painted black to keep stray light from bouncing off of them and creating flare in the image. It is probably not enough to cause much concern at this stage - when it gets bad enough, with care it can be removed (once it separates it can be chipped off) and repainted. Any good black enamel, either gloss or matte finish, will work. Of course, this involves disassembling the lens and taking care to protect the working surfaces of the glass. |
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