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Thread: Black card??

  1. #21
    Senior Member edutilos-'s Avatar
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    Default Re: Black card??

    Quote Originally Posted by farbird View Post
    erm... say I use a hand held fan to get the required frequency to block the scene [ ie reduce light going in ?] hehhe..

    will experiment and let u guys know
    Why don't you just try to wave the fan in front of the camera and see if you can prevent the camera from freezing the motion. If you can, then it will work.

    I doubt you can. Cheers.

  2. #22

    Default Re: Black card??

    Quote Originally Posted by edutilos- View Post
    Why don't you just try to wave the fan in front of the camera and see if you can prevent the camera from freezing the motion. If you can, then it will work.

    I doubt you can. Cheers.
    Maybe this would work? Can DIY the fan baldes to become black.


    But seriously, black card cannot be used as ND filter. GND can, but not ND.

  3. #23
    Moderator catchlights's Avatar
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    Default Re: Black card??

    the black card is not transparent, no matter how fast you move, it still record the card in a very faint image,
    to cut down more light reach the sensor, you need to record more of the black card
    in the end you get a very low contrast image.

    So, just .......... get ............. a .............. ND ................. filter.
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  4. #24

    Default Re: Black card??

    Quote Originally Posted by catchlights View Post
    the black card is not transparent, no matter how fast you move, it still record the card in a very faint image,
    to cut down more light reach the sensor, you need to record more of the black card
    in the end you get a very low contrast image.

    So, just .......... get ............. a .............. ND ................. filter.
    Fill in the blanks?

    Anyway, black card doesn't exactly substitute GND. It blocks light from going to the sensor, while GND reduces light going on the sensor. Movement effects will be more pronounced with GND/ND filter.

    For example, if your exposure is 30s and your sky is 1 stop over for that exposure, you need to bring the sky down by 1 stop. If you use a 1 stop GND, your exposure in the sky will be 30s. If you use black card to block the light, your sky will be a 15s exposure while your foreground will still be 30s. If you don't mind/want movement effects in the sky then the black card will be good, but if you want it, then you should get a GND filter.

  5. #25

    Default Re: Black card??

    Quote Originally Posted by brapodam View Post
    Fill in the blanks?

    Anyway, black card doesn't exactly substitute GND. It blocks light from going to the sensor, while GND reduces light going on the sensor. Movement effects will be more pronounced with GND/ND filter.

    For example, if your exposure is 30s and your sky is 1 stop over for that exposure, you need to bring the sky down by 1 stop. If you use a 1 stop GND, your exposure in the sky will be 30s. If you use black card to block the light, your sky will be a 15s exposure while your foreground will still be 30s. If you don't mind/want movement effects in the sky then the black card will be good, but if you want it, then you should get a GND filter.
    actually for slow movements, like cloud movement, you may be still able to get similar result by using black card, in your example above, 30 secs foreground and 15 secs for sky, you don't necessarily need to expose 15 secs at one go, you can choose to expose the sky for 5 secs every 10 secs, or even 3 secs every 6 secs, so after 30 secs you will still have total 15 secs exposure for the sky, but you have captured the movement of the clouds over a period of 30 seconds.

    of course a GND will be convenient but black card can sometimes offer more flexibility.
    Last edited by miaoteh; 13th March 2012 at 09:06 PM.

  6. #26

    Default Re: Black card??

    Quote Originally Posted by miaoteh View Post
    actually for slow movements, like cloud movement, you may be still able to get similar result by using black card, in your example above, 30 secs foreground and 15 secs for sky, you don't necessarily need to expose 15 secs at one go, you can choose to expose the sky for 5 secs every 10 secs, or even 3 secs every 6 secs, so after 30 secs you will still have total 15 secs exposure for the sky, but you have captured the movement of the clouds over a period of 30 seconds.

    of course a GND will be convenient but black card can sometimes offer more flexibility.
    Yes I understand that. It is possible but much harder to do, though I agree that a black card is more flexible than a GND.

  7. #27

    Default Re: Black card??

    Quote Originally Posted by i-Noob View Post
    Hi guys, I've read a few forums included Hanjie's blogs, but I still I don't really understand this black card methods.. Is the card totally black in color or just a piece of transparency in black color?
    Hi there, you can actually use black foam boards (they are flexible and you can mould them into various shapes to dodge the exposure of highlights in your scene) or even a black glove. Personally, I use a black piece of cardboard and a foam board. Do make sure that it is as non-reflective as possible. Also, if there are sources of light around the camera, light-leak may occur too, so it's best to either have something block those lights, or use a black cloth/foam board (you can 'wrap' these around the lens to prevent the extra light from getting in).

    Usually, I would spot-meter both the sky (highlights) and the foreground of a scene before using the black card to compensate for the difference in the difference in exposure. Of course, using an ND filter would help greatly in this aspect. For example, if the meter for the sky reads 1/200 at f/11, and 1/15 at the same aperture for the foreground, I'll pop in a ND-filter (usually a Hoya 9-stop) to give me an equivalent exposure of 2s for the sky and 27s for the foreground. I'll usually over-exposure the foreground a little bit more to get the exposure a little more even. It's actually a pretty straightforward technique and you should try it out! Cheers.

  8. #28

    Default

    Thank you so much for all the great inputs

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