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Thread: bulb mode of EOS cam.....

  1. #1

    Default bulb mode of EOS cam.....

    lets say if i set my shutter spd to bulb mode.......
    and i take a pic.....
    how the camera will know how long i will press......so that it can set the correct aperture??????
    i can press 1 min.......or even 1 hour....
    wont the pic be overexposed in that case???

  2. #2
    Senior Member Kit's Avatar
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    If you're using bulb setting, the camera will be in fully manual mode, therefore the camera will not set the aperture for you. Its all done manually. What do you need the bulb setting for?

  3. #3

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    u will have to do a manual calculation on how long u will have to hold the shutter open with accompanying aperture values at certain ISO values

  4. #4

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    but its still in tv mode right?

  5. #5

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    nope. TV mode does not allow bulb exposures... only available in Manual Mode

  6. #6

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    Originally posted by mervlam
    u will have to do a manual calculation on how long u will have to hold the shutter open with accompanying aperture values at certain ISO values
    and how do u calculate that?

  7. #7

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    Ayumi, bulb mode exposure is a pretty advanced topic. I think you should try out some night photography first and understand exposure metering using different modes before exploring this area. Would really like to help but dunno where to shart...

  8. #8

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    i am thinking of taking the spore skyline lor......
    coz i am really inspired by one of the photo here......

    i need a longer shutter speed.....so that the boat has enuff time to travel from under the bridge.......all the way to the quay.......

    my camera max shutter speed is only 30s.....definately need a longer shutter speed........maybe around 2 mins???

    have to go down there and time the boat......
    haha

  9. #9

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    Originally posted by David
    Ayumi, bulb mode exposure is a pretty advanced topic. I think you should try out some night photography first and understand exposure metering using different modes before exploring this area. Would really like to help but dunno where to shart...
    yup... i learnt it that way.. plus pick up some books on basic photography... they help very much. but of course u can clear some doubts here

  10. #10

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    Originally posted by Ayumi
    i am thinking of taking the spore skyline lor......
    coz i am really inspired by one of the photo here......

    i need a longer shutter speed.....so that the boat has enuff time to travel from under the bridge.......all the way to the quay.......

    my camera max shutter speed is only 30s.....definately need a longer shutter speed........maybe around 2 mins???

    have to go down there and time the boat......
    haha
    the chinese junk??? comes into the harbour around 2010 to 2030.... last about 2 to 3 mins... went there a few days ago

  11. #11
    Senior Member Kit's Avatar
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    .
    Last edited by Kit; 25th May 2002 at 03:19 AM.

  12. #12

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    I know nothing about bulb exposure, but I would like to propose a basic way of calculating the right exposure, and hope experts here can comment the feasibility?

    First set the aperture such that the shutter speed is within 30s, as metered by the camera (all EV compensation taken in account already). Let's say at F11, the shutter speed is 30s. Say if I want to expose for 2 mins, and 30 x 2 x 2 = 120 so that's 2 stops more. So the corresponding aperture will be F11 x 2 = F22.

    Then I'll just go into manual mode, set F22, bulb. Then when activating the shutter, wait for 2min.

    Is this feasible?

  13. #13
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    Originally posted by Ayumi
    i am thinking of taking the spore skyline lor......
    coz i am really inspired by one of the photo here......

    i need a longer shutter speed.....so that the boat has enuff time to travel from under the bridge.......all the way to the quay.......

    my camera max shutter speed is only 30s.....definately need a longer shutter speed........maybe around 2 mins???

    have to go down there and time the boat......
    haha
    A few things to watch out when using bulb.

    1. be aware of reciprocity failure of films.
    2. you need a strong tripod, at least a M190 if possible.
    3. you need to buy a cable release as keep pressing on the shutter button will introduce vibrating. (not to mention hand getting tired)
    4. remember to cover you eyepiece using the eye piece cover which is normally found as a piece of plastic on the neck strip.
    5. a watch with the second hand, eletronic one better.

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