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Thread: Polarizing filter - improvised?

  1. #1
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    Polarizing filter - improvised?

    My ride camera is a Canon A710IS p&s, which has served me well. My usual picture taking procedure is to stop the bike, put down the side stand, get the camera from the tank bag, walk a few feet or yards to a good spot, compose, and shoot (95% scenery shots).

    BUT, I would like to use a polarizing filter and the A710 has no provision for accepting threaded-on filters. My questions: is there any practical way to attach a filter to this kind of camera? Could I buy a small sheet of polarizing plastic sheet and simply hold it in front of the lens? If so, who sells it?

    I'm just a hobbyist so I could accept some reduction in photo quality, and I'd be able to use my left hand to hold something in front of the lens, if it comes to that. For me, part of the enjoyment of riding is to take a few impressive scenery shots for friends and family - I edit for max saturation and maybe I could enhance them further with the filter.

  2. #2
    @ the Big Muddy & I-80 bluestune's Avatar
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    Improvised polarizing filter

    Hand holding a polarizing filter in front of a point and shoot camera will be cumbersome, at best. But, if you want to give it a try, you might try this: set your point and shoot camera to overexpose by one and a half f-stops, then compose your shot, press the shutter release halfway down to lock the focus and exposure, then hold and rotate the polarizing filter in front of the camera lens and trip the shutter. You may have to adjust the amount of exposure adjustment to your taste.

    A polarizing filter uses an extra stop and a half of light, that's why you need to set the camera to overexpose. Also, as you probably know, you have to rotate the polarizing filter to see the effect.

    I have not yet tried this on my point and shoot camera, but I'll give it a shot this week.

    Good luck.

    Dave
    1976 R90/6

  3. #3
    rocketman
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    Check out this item



    Canon LA-DC58G Conversion Lens Adapter for the Canon A700, A710IS & A720IS Digital Cameras

    24.95 on Amazon

    it has a 58mm internal thread that should work any with filters such as

    this 58 mm polarizing filter



    Opteka 58mm High Definition?? Multi-Coated Circular Polarizing Glass Filter

    $13.00 also on Amazon

    not that I am recommending Amazon or its products, just to give you an idea for the prices, seems very reasonable for the extra versatility, I use the similar adapter for my G9 all the time.

    and you could also get some Cokin filters that have a holder for up to three filters at at time such as Graduated ND filters, colored filters and star filters etc.

    other accessories include

    Accessories

    * Conversion Lens Adapter (LA-DC58G)
    * Wide-Converter 0.7x lens (WC-DC58N)
    * Tele-Converter 1.75x lens (TC-DC58N)
    * Close-Up Lens 250D (58mm)
    * Battery and Charger Kit (CBK4-300)
    * High Power Flash (HF-DC1)

    RM

  4. #4
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    Rocketman - Good call. Thanks. I had forgotten about that removable accessory ring around the camera's lens housing. The Canon adapter and some filters seems like a good solution.

    Dave - Wouldn't this camera automatically take into account any polarizing material in front of the lens (unless I had the camera in some manual mode)? Waving a polarizing sheet, if I can find one, in front of the lens would be an interesting experiment.

  5. #5
    @ the Big Muddy & I-80 bluestune's Avatar
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    Thumbs up

    Yes, sort of. As long as the camera doesn't focus on the polarizer, and as long as the camera meter can meter properly through the filter. Some camera meters don't like some polarizing filters and will cause improper exposure. What you're talking about might work great, I'd sure give it a try. But keep in mind, most polarizing sheets are designed for placement over copy lights, not shooting through, so you might end up with some soft images.

    The attachments Rocketman talks about look great and should work fine with the Canon 710A. Your camera has a retractable lens, so, just be sure to remove any attachments before you turn off the power and retract the lens. And, be cautious when attaching anything to the front of any retractable lens, you don't want to strip the gears or move the lens out of alignment.

    I look forward to viewing your results. Good luck!

    Dave
    1976 R90/6

  6. #6
    Seattle-area Rounder OfficerImpersonator's Avatar
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    Wouldn't it be somewhat safe to assume that the Canon image processor, code and optics are likely designed to accomodate a polarizing filter? I would bet that they don't tweak too much of the code, or change too much of the hardware, between a mid-level point and shoot, a high-level point and shoot, and even the digital Rebels - which has an image processor that most certainly deals with polarized filters.

    I keep mine on all the time - I have one on the end of each of my three lenses. Replacing a $30 - $50 filter due to wear and tear or calamity is way cheaper than replacing the entire lens.

    My question, then, is what am I loosing by taking every shot through a polarized filter?
    Seattle, WA
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  7. #7
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by OfficerImpersonator View Post
    Wouldn't it be somewhat safe to assume that the Canon image processor, code and optics are likely designed to accomodate a polarizing filter?
    My SLR requires a circular polarizer. Don't know about a P&S.

    Quote Originally Posted by OfficerImpersonator View Post
    My question, then, is what am I loosing by taking every shot through a polarized filter?
    You loose 1 - 2 stops, depending upon the filter. You may not be able to pan/create panorama and expect the colors in the various shots to match. The sky might be different colors on very wide angle shots.

    // marc

  8. #8
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by marchyman View Post
    My SLR requires a circular polarizer.
    Requires?
    Best for me is "RAW" and Photoshop.
    Only glass I put over my lenses is a UV filter used as a "clear lens cap"...
    "Stupidity, if left untreated, is self-correcting."

  9. #9
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by grafikfeat View Post
    Requires?
    Best for me is "RAW" and Photoshop.
    Only glass I put over my lenses is a UV filter used as a "clear lens cap"...
    How about I word that differently. It is the "circular" part that is required, not the polarized part. How about this wording:

    If I'm going to use a polarized filter my camera requires it to be circularly polarized for proper operation.

    That better?

    // marc

  10. #10
    "Running Out The Clock" grafikfeat's Avatar
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    Quote Originally Posted by marchyman View Post
    How about I word that differently. It is the "circular" part that is required, not the polarized part. How about this wording:

    If I'm going to use a polarized filter my camera requires it to be circularly polarized for proper operation.

    That better?

    // marc
    There ya go... That wasn't so bad... Was it? Making oneself clear?

    Much Better.
    "Stupidity, if left untreated, is self-correcting."

  11. #11
    Seattle-area Rounder OfficerImpersonator's Avatar
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    Quote Originally Posted by marchyman View Post
    My SLR requires a circular polarizer. Don't know about a P&S.



    You loose 1 - 2 stops, depending upon the filter. You may not be able to pan/create panorama and expect the colors in the various shots to match. The sky might be different colors on very wide angle shots.

    // marc
    Thanks for the info - I think I'll switch to a plain 'ol UV filter as my "clear lens cap".
    Seattle, WA
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    2002 R1150RT-P
    1992 K75S sold

  12. #12
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    I'm the OP here and I've taken the excellent suggestion to get the genuine Canon adapter and some filters.

    Regarding the polarizing filter, it is described as "circular" as though that's a particular method of polarzing. What is meant by "circular"? Of course its shape is circular but I don't see anything circular about how it polarizes.

  13. #13
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by Sailorlite View Post
    I'm the OP here and I've taken the excellent suggestion to get the genuine Canon adapter and some filters.

    Regarding the polarizing filter, it is described as "circular" as though that's a particular method of polarzing. What is meant by "circular"? Of course its shape is circular but I don't see anything circular about how it polarizes.
    Tiffen says at http://www.tiffen.com/polarizer_pics.htm

    Certain camera optical systems employ internal surfaces that themselves polarize light. Using a standard (linear) polarizer will cause the light to be further absorbed by the internal optics, depending on the relative orientation. A Circular Polarizer is a linear one to which has been added,on the side facing the camera, a quarter wave "retarder." This "corkscrews" the plane of polarization, effectively depolarizing it, eliminating the problem. The Circular Polarizer otherwise functions in the same manner.

    Yeah, that doesn't mean much to me, either.

    // marc

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