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Thread: Filters and Large(r) Apertures... Help

  1. #11

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    Re: Filters and Large(r) Apertures... Help

    Quote Originally Posted by xkaes View Post
    Given the prices they charge for their ND filters, you deserve an accurate filter, as well as a free night at a luxury hotel.

    Your test methods leave a lot to be desired but since I don't know your gear, all I can suggest is to put your camera on a steady support. Then meter a blank, midtone scene, such as a gray card or evenly illuminated wall -- with and without the ND filters. Hopefully your camera gives you some sort of f-stop and shutter speed readout that you can compare. Without that, I'm afraid you are just using your eyeball -- not too accurate.
    Haha, yes. They are pricey and only one of the reasons I can't afford to stay in a luxury hotel.

    Thanks for the tip. I'll try this method next and see what comes of it. And yes, my eyeballs have a lot to be desired.

  2. #12

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    Re: Filters and Large(r) Apertures... Help

    Quote Originally Posted by Leigh View Post
    Digital cameras are less than worthless for objective analysis. They're deceptive and manipulative.

    They take a meter reading, then manipulate it to achieve the "best" appearance assuming a human subject.

    Absolutely invalid for any reliable testing since they don't tell you what the algorithm is.

    Get a hand-held exposure meter, preferably of the vintage variety though it really doesn't matter.
    Use a sunlit white wall as the subject, standing where your shadow is not in the metered area.
    Meter the wall without the filter, then with.

    - Leigh

    I agree 100% re. digital cameras. I just don't want to experiment with actual film.

    I am using a dedicated light meter. Always. Just taking the reading off of that and adjusting the settings on my camera.

    I'll definitely try the method you described.

    Thanks for your help and input!

  3. #13
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: Filters and Large(r) Apertures... Help

    Quote Originally Posted by seandavid View Post
    I agree 100% re. digital cameras. I just don't want to experiment with actual film.
    The problem with digital cameras is they don't always give you the same information.

    Film always responds the same way to the same conditions.

    Admittedly, testing with film costs money, which is why I suggested a hand-held exposure meter.

    - Leigh
    Last edited by Leigh; 22-Jun-2017 at 09:52.
    If you believe you can, or you believe you can't... you're right.

  4. #14

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    Re: Filters and Large(r) Apertures... Help

    If you are using a hand-held, reflectance meter, a little caution is in order. Since it is an ND filter, if you simply hold the filter in front of the meter, some extraneous light might hit the meter's sensor -- stray light from the side or reflecting back off of the filter. So get the filter as close as you can to the meter's sensor. Sometimes having four hands helps.

  5. #15

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    Re: Filters and Large(r) Apertures... Help

    Quote Originally Posted by xkaes View Post
    If you are using a hand-held, reflectance meter, a little caution is in order. Since it is an ND filter, if you simply hold the filter in front of the meter, some extraneous light might hit the meter's sensor -- stray light from the side or reflecting back off of the filter. So get the filter as close as you can to the meter's sensor. Sometimes having four hands helps.
    Exactly. When I tested my ND gels I used my Sinar (monorail) camera with a bellows hood in front of the camera and a filter holder located between the hood and the camera; the hood kept all stray light off the front surface of the filter, then I removed the camera back so I could use a spot meter through the camera bellows and put a darkcloth over the camera and hood to keep stray light off the rear surface of the filter. Used blue floods (to simulate outdoor lighting) evenly illuminating a white mount board. All this setup was possibly overkill, but the filter factors were all exactly what the manufacturer said they were.

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