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Thread: Oil in Hoya CPL filter

  1. #1
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    Default Oil in Hoya CPL filter

    Hi

    I have a Hoya 58mm CPL filter about 10 yrs old. I notice there is some oil-like substance present between the two glass elements of the CPL filter for those for u who know CPL filters can be turn 'horizontally' and 'vertically'.

    Is it due to heat that the oil surfaced in the filter? I wonder how to remove that oil? Thanks. Or shd i just go get another CPL filter?

  2. #2
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    Mar 2008
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    Singapore
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    Default Re: Oil in Hoya CPL filter

    Hi,

    Just a thought. In a CPL filter, one should not be able to see any liquid or oil in the in between the 2 glasses cos its costed evenly. If you are able to see blobs of oil, then the oil will have start to dry, hence unable to coat the entire 58 mm glass pieces. One possible reason may be due to it being stored in very low humidity environment like a 20+% RH dry box.

    For the oil not to dry up, perhaps you can consider 50-60% RH environment such as dry cabinets and if you are using dry box, do not put in excessive silica gel beads. Lab tests I have done in my course of work show just a little silica beads (1 small handful) can bring the RH levels in a small box (such as dry boxes) to as low as 21% RH.

    Just some food for thought. I may be incorrect.

    Have a nice time at work/school.

    Cheers,
    Regards,
    Herman

  3. #3
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    Default Re: Oil in Hoya CPL filter

    Quote Originally Posted by hermes129 View Post
    Hi,

    Just a thought. In a CPL filter, one should not be able to see any liquid or oil in the in between the 2 glasses cos its costed evenly. If you are able to see blobs of oil, then the oil will have start to dry, hence unable to coat the entire 58 mm glass pieces. One possible reason may be due to it being stored in very low humidity environment like a 20+% RH dry box.

    For the oil not to dry up, perhaps you can consider 50-60% RH environment such as dry cabinets and if you are using dry box, do not put in excessive silica gel beads. Lab tests I have done in my course of work show just a little silica beads (1 small handful) can bring the RH levels in a small box (such as dry boxes) to as low as 21% RH.

    Just some food for thought. I may be incorrect.

    Have a nice time at work/school.

    Cheers,


    Thanks for reply. Now that u mentioned think my filter is seldom used and lies in too low humidity. That probably explains why. So theoretically the oil will disappear eventually if i place the filter in RH humidity levels of 50 to 60%? Or place the filter in room temperature and room humidity levels.

  4. #4
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    Join Date
    Mar 2008
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    Singapore
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    69

    Default Re: Oil in Hoya CPL filter

    Hi,

    My guess is that the oil blob will not disappear as the coating is already uneven. I guess the coating is optimal for the CPL filter in the first place, so if it started to dry, the CPL filter will have spoilt. You can try to press it even on the glass surface but once you release the pressure, I believe the oil blob will re-appear. My suggestion is that you will need to re-purchase the filter if you need to use it.

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