Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,571   Posts: 1,545,594   Online: 992
      
Results 1 to 3 of 3
  1. #1

    Join Date
    Jan 2005
    Location
    Houston, Texas
    Shooter
    Medium Format
    Posts
    177

    Cleaning a petzval

    I think I already know the answer to this, but what the heck, I'll ask anyway.
    I recently bought a Bausch and Lomb petzval lens off a really old projector. In fact I bought the entire projector, but since the shipping cost was huge (more than the value of the item), I had him just take off the lens and send it. I told him to just resell the projector without the lens if he wanted.
    I can just unscrew the front piece and clean the front lens with no problem. The rear is a different story. There seems to be some kind of haze inside the two rear elements. It looks a bit like condensation, but it's not. It's most likely fungus. I'm pretty sure that's what I'm dealing with.
    Here's the dumb question: Is there anything I can about it? I can't get to the inside of the elements. They appear to be glued in.
    Thanks,
    Steve
    www.scdowellphoto.com

  2. #2

    Join Date
    Dec 2007
    Shooter
    Large Format
    Posts
    79
    There are two types of these B&L projector lenses. If it's the petzval (the other is a triplet) the rear two should be separable, if you can get them out of course. Usually there is a threaded ring inside the rear group. Unscrewing it is difficult, but if you use a piece of nonstick rubber (the thin type for getting jar lids off) you can usually get it started. Once the ring is out, the two lenses and separator just slide out.

  3. #3

    Join Date
    Jan 2005
    Location
    Houston, Texas
    Shooter
    Medium Format
    Posts
    177
    Thanks for the reply. I can't see any of kind threaded ring near the rear elements. They just seem to be glued in on some sort of ledge, It's hard to tell. I suppose it could be the triplet, but I thought it was a petzval. The rear element is very thick if it's one piece. Maybe an inch thick.
    I've read that fungus can be cleared up if exposed to UV light. I assume that would kill the fungus, but leave the residue behind. Correct?
    I haven't used the lens yet. It may be ok with the haze, but obviously I'd like to clean it up.
    Thanks,
    Steve
    www.scdowellphoto.com



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin