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Thread: Cpl filter affect lens focus

  1. #1

    Default Cpl filter affect lens focus

    Hi guys, anyone experienced when using cpl filter it change the focus of ur lens?
    I just send my Sigma 70-300 for calibration, im very happy on the focus but yesterday when i tried using it with cpl ( a cheap one ) i got a blurred pics and even I checked on LV the subject is OOF. When I changed it back with UV filter the focus is just fine, so I suspect its because of the cpl filter. Does cheaper filters affect the lens focus?

  2. #2
    Moderator Octarine's Avatar
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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Hi guys, anyone experienced when using cpl filter it change the focus of ur lens?
    I just send my Sigma 70-300 for calibration, im very happy on the focus but yesterday when i tried using it with cpl ( a cheap one ) i got a blurred pics and even I checked on LV the subject is OOF. When I changed it back with UV filter the focus is just fine, so I suspect its because of the cpl filter. Does cheaper filters affect the lens focus?
    What else does it need to proof your suspicion? But it's not that your topic is new .. it's popping up every week. Welcome to the club. Get quality filters, period.
    Beside this: I don't see how any lens calibration can change this. A bit wasted money, imho.
    EOS

  3. #3

    Default Re: Cpl filter affect lens focus

    Does not matter whether the glass is cheap or not. Get a more trusted or renowned brand of CPL to test it out and convince yourself.

    You do photography to convince yourself, not others. Cheers
    S5Pro, Nikon 70-210 f4,Tamron 17-50mm f2.8

  4. #4

    Default Re: Cpl filter affect lens focus

    thanks guys, I will get another cpl, a quality one.

  5. #5
    Senior Member ovaltinemilo's Avatar
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    Default Re: Cpl filter affect lens focus

    got pic to see? of course it's always better to invest in a reasonable CPL. but oof is abit too much..haha...
    ...:::..::.Nikon.::.:::..
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  6. #6

    Default Re: Cpl filter affect lens focus

    its really OOF, that's why my initial thought its because of the calibration but when I tried with my uv filter its fine.
    maybe its what u get when u want a cheaper one. hehehe
    must invest with quality filter, lesson learned.

  7. #7
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    Default Re: Cpl filter affect lens focus

    While having quality filters does matter, I would advise you to check another 2 things:
    1. Does the front element rotate when focusing? (I'm not a Sigma user, hence I don't know and have to ask you to check.) This problem is usually more pronouced when using CPL as compared to UV filters due to the need to rotate the CPL to get the desired effect.
    2. CPLs generally reduce by 2 stops, whereas UV filters should not. Did your shutter speed decrease (causing camera shake, unless you were on tripod and using remote) when comparing the 2 photos?

    Just my newbie $0.02.

  8. #8

    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by arctos View Post
    While having quality filters does matter, I would advise you to check another 2 things:
    1. Does the front element rotate when focusing? (I'm not a Sigma user, hence I don't know and have to ask you to check.) This problem is usually more pronouced when using CPL as compared to UV filters due to the need to rotate the CPL to get the desired effect.
    2. CPLs generally reduce by 2 stops, whereas UV filters should not. Did your shutter speed decrease (causing camera shake, unless you were on tripod and using remote) when comparing the 2 photos?

    Just my newbie $0.02.
    Bro I used tripod and shoot the flag hanging opposite my flat, I tried to rotate the filter but still OOF.
    Maybe next time I will buy CPL must bring my gadget to try.

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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Bro I used tripod and shoot the flag hanging opposite my flat, I tried to rotate the filter but still OOF.
    Maybe next time I will buy CPL must bring my gadget to try.
    Ok, tripod means camera shake due to longer exposure unlikely. But you were shooting a flag hanging outside - wind movement could make it "blur" too.

    Oh, and precisely coz you tried to rotate the filter, that could throw the focus off-balance if you have a rotating front element. Erm I hope someone more eloquent than me can explain this.

  10. #10

    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by arctos View Post
    Ok, tripod means camera shake due to longer exposure unlikely. But you were shooting a flag hanging outside - wind movement could make it "blur" too.

    Oh, and precisely coz you tried to rotate the filter, that could throw the focus off-balance if you have a rotating front element. Erm I hope someone more eloquent than me can explain this.
    Bro I used tripod to make sure that the blurred pics not due to my handshake.
    Sony has built in SS, that's why when I shoot again w/o the cpl the pics were sharp even w/o tripod.

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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Hi guys, anyone experienced when using cpl filter it change the focus of ur lens?
    I just send my Sigma 70-300 for calibration, im very happy on the focus but yesterday when i tried using it with cpl ( a cheap one ) i got a blurred pics and even I checked on LV the subject is OOF. When I changed it back with UV filter the focus is just fine, so I suspect its because of the cpl filter. Does cheaper filters affect the lens focus?
    can share what cpl brand u use?

  12. #12
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    Default Re: Cpl filter affect lens focus

    Juz asking.. Are you sure it is a CPL and not PL?

    Normal polariser WILL affect AF.. CPL is needed for cameras with AF..

  13. #13
    Senior Member ovaltinemilo's Avatar
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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Bro I used tripod to make sure that the blurred pics not due to my handshake.
    Sony has built in SS, that's why when I shoot again w/o the cpl the pics were sharp even w/o tripod.
    was it that the wind stopped blowing?
    ...:::..::.Nikon.::.:::..
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    Default Re: Cpl filter affect lens focus

    i saw a CPL which does not work with Canon 55-250 IS lens..
    it either off-focuses or totally fails to focus when put on..
    but it works well with the 18-55 IS kit lens..

  15. #15

    Default Re: Cpl filter affect lens focus

    Actually just bought it from someone who ads his product here at CS, made in china the brand is L-GREEN.

  16. #16

    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by Limsgp View Post
    Juz asking.. Are you sure it is a CPL and not PL?

    Normal polariser WILL affect AF.. CPL is needed for cameras with AF..
    Its says in the label that its CPL.
    I tried using AF and MF and the result still OOF.

  17. #17
    Moderator daredevil123's Avatar
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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Its says in the label that its CPL.
    I tried using AF and MF and the result still OOF.
    It is probably not OOF la. Just that the pictures are generally soft.. not OOF.

    Question for you: did you remove the UV/protection filter before putting on the CPL? Or did you stack the CPL over the UV filter?

  18. #18

    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by daredevil123 View Post
    It is probably not OOF la. Just that the pictures are generally soft.. not OOF.

    Question for you: did you remove the UV/protection filter before putting on the CPL? Or did you stack the CPL over the UV filter?
    its really blurred. even i used the MF CHECK LV and zoom in the subject still OOF, the pics came out with shadows on the stars and moon. yes i removed the uv filter

  19. #19

    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    Actually just bought it from someone who ads his product here at CS, made in china the brand is L-GREEN.
    I have know someone that uses tat china brand filter b4 and image came out blur. Well if its down to the filter, change it. Very simple and not need to argue what else went wrong...
    S5Pro, Nikon 70-210 f4,Tamron 17-50mm f2.8

  20. #20
    Moderator daredevil123's Avatar
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    Default Re: Cpl filter affect lens focus

    Quote Originally Posted by baynald12 View Post
    its really blurred. even i used the MF CHECK LV and zoom in the subject still OOF, the pics came out with shadows on the stars and moon. yes i removed the uv filter
    It is blur, and not out-of-focus.

    If it is out-of-focus, you should be able to detect another object in another plane to be in focus.

    You subject is in focus. But the entire picture is soft. Very different thing, OOF and blur(soft), two different concepts.

    in the old days, I had a cheap uncoated Hoya UV filter, and a cheap uncoated Hoya CPL. One nice sunny day, I stacked the CPL on top of the UV and shot. The pics came up all blur. After half a day, I removed the CPL, the pics became sharp again. Here is an example:

    Stacked filters:


    Only UV on the same day:
    Last edited by daredevil123; 22nd July 2010 at 11:06 AM.

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